Replace handshake over in flight transmit

Fix deadloop in DTLS resumption test.

Signed-off-by: Jerry Yu <jerry.h.yu@arm.com>
diff --git a/library/ssl_msg.c b/library/ssl_msg.c
index 5d56dd6..eae1dde 100644
--- a/library/ssl_msg.c
+++ b/library/ssl_msg.c
@@ -2343,7 +2343,7 @@
         return( ret );
 
     /* Update state and set timer */
-    if( mbedtls_ssl_is_handshake_over( ssl ) == 1 )
+    if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER )
         ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED;
     else
     {