Rename SSL_RENEGOTIATION macro

- new name is more explicit
- avoids collision with POLARSSL_SSL_RENEGOTIATION config flag when prefixing
  will be applied
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index 1244435..ab9eeed 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -120,7 +120,7 @@
 
     *olen = 0;
 
-    if( ssl->renegotiation != SSL_RENEGOTIATION )
+    if( ssl->renegotiation != SSL_RENEGOTIATION_IN_PROGRESS )
         return;
 
     SSL_DEBUG_MSG( 3, ( "client hello, adding renegotiation extension" ) );
@@ -1195,7 +1195,7 @@
     if( ssl->in_msgtype != SSL_MSG_HANDSHAKE )
     {
 #if defined(POLARSSL_SSL_RENEGOTIATION)
-        if( ssl->renegotiation == SSL_RENEGOTIATION )
+        if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS )
         {
             ssl->renego_records_seen++;
 
@@ -1581,21 +1581,21 @@
         handshake_failure = 1;
     }
 #if defined(POLARSSL_SSL_RENEGOTIATION)
-    else if( ssl->renegotiation == SSL_RENEGOTIATION &&
+    else if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
              ssl->secure_renegotiation == SSL_SECURE_RENEGOTIATION &&
              renegotiation_info_seen == 0 )
     {
         SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
         handshake_failure = 1;
     }
-    else if( ssl->renegotiation == SSL_RENEGOTIATION &&
+    else if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
              ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
              ssl->allow_legacy_renegotiation == SSL_LEGACY_NO_RENEGOTIATION )
     {
         SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
         handshake_failure = 1;
     }
-    else if( ssl->renegotiation == SSL_RENEGOTIATION &&
+    else if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
              ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
              renegotiation_info_seen == 1 )
     {
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 59c1c1e..499fe06 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -1189,7 +1189,7 @@
         {
             SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
 #if defined(POLARSSL_SSL_RENEGOTIATION)
-            if( ssl->renegotiation == SSL_RENEGOTIATION )
+            if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS )
             {
                 SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV "
                                     "during renegotiation" ) );
@@ -1805,7 +1805,7 @@
         case TLS_EXT_SIG_ALG:
             SSL_DEBUG_MSG( 3, ( "found signature_algorithms extension" ) );
 #if defined(POLARSSL_SSL_RENEGOTIATION)
-            if( ssl->renegotiation == SSL_RENEGOTIATION )
+            if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS )
                 break;
 #endif
 
@@ -1941,7 +1941,7 @@
         if( p[0] == 0 && p[1] == SSL_EMPTY_RENEGOTIATION_INFO )
         {
             SSL_DEBUG_MSG( 3, ( "received TLS_EMPTY_RENEGOTIATION_INFO " ) );
-            if( ssl->renegotiation == SSL_RENEGOTIATION )
+            if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS )
             {
                 SSL_DEBUG_MSG( 1, ( "received RENEGOTIATION SCSV during renegotiation" ) );
 
@@ -1965,21 +1965,21 @@
         handshake_failure = 1;
     }
 #if defined(POLARSSL_SSL_RENEGOTIATION)
-    else if( ssl->renegotiation == SSL_RENEGOTIATION &&
+    else if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
              ssl->secure_renegotiation == SSL_SECURE_RENEGOTIATION &&
              renegotiation_info_seen == 0 )
     {
         SSL_DEBUG_MSG( 1, ( "renegotiation_info extension missing (secure)" ) );
         handshake_failure = 1;
     }
-    else if( ssl->renegotiation == SSL_RENEGOTIATION &&
+    else if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
              ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
              ssl->allow_legacy_renegotiation == SSL_LEGACY_NO_RENEGOTIATION )
     {
         SSL_DEBUG_MSG( 1, ( "legacy renegotiation not allowed" ) );
         handshake_failure = 1;
     }
-    else if( ssl->renegotiation == SSL_RENEGOTIATION &&
+    else if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
              ssl->secure_renegotiation == SSL_LEGACY_RENEGOTIATION &&
              renegotiation_info_seen == 1 )
     {
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index 5e9df52..d474ccd 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -3206,7 +3206,7 @@
          * except at the beginning of renegotiations */
         if( ssl->in_msgtype == SSL_MSG_APPLICATION_DATA &&
             ssl->state != SSL_HANDSHAKE_OVER &&
-            ! ( ssl->renegotiation == SSL_RENEGOTIATION &&
+            ! ( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS &&
                 ssl->state == SSL_SERVER_HELLO ) )
         {
             SSL_DEBUG_MSG( 1, ( "dropping unexpected ApplicationData" ) );
@@ -3942,7 +3942,7 @@
      */
 #if defined(POLARSSL_SSL_RENEGOTIATION) && defined(POLARSSL_SSL_CLI_C)
     if( ssl->endpoint == SSL_IS_CLIENT &&
-        ssl->renegotiation == SSL_RENEGOTIATION )
+        ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS )
     {
         if( ssl->session->peer_cert == NULL )
         {
@@ -4487,7 +4487,7 @@
     SSL_DEBUG_MSG( 3, ( "=> handshake wrapup" ) );
 
 #if defined(POLARSSL_SSL_RENEGOTIATION)
-    if( ssl->renegotiation == SSL_RENEGOTIATION )
+    if( ssl->renegotiation == SSL_RENEGOTIATION_IN_PROGRESS )
     {
         ssl->renegotiation =  SSL_RENEGOTIATION_DONE;
         ssl->renego_records_seen = 0;
@@ -5979,7 +5979,7 @@
 #endif
 
     ssl->state = SSL_HELLO_REQUEST;
-    ssl->renegotiation = SSL_RENEGOTIATION;
+    ssl->renegotiation = SSL_RENEGOTIATION_IN_PROGRESS;
 
     if( ( ret = ssl_handshake( ssl ) ) != 0 )
     {
@@ -6022,7 +6022,7 @@
      * On client, either start the renegotiation process or,
      * if already in progress, continue the handshake
      */
-    if( ssl->renegotiation != SSL_RENEGOTIATION )
+    if( ssl->renegotiation != SSL_RENEGOTIATION_IN_PROGRESS )
     {
         if( ssl->state != SSL_HANDSHAKE_OVER )
             return( POLARSSL_ERR_SSL_BAD_INPUT_DATA );