Fix possible race in ssl_list_ciphersuites()

Thread A: executing for loop of ssl_list_ciphersuites()
Thread B: call ssl_list_cipher_suites(), see init == 0
Thread A: return, start using the result
Thread B: memset(0) on the list used by thread A
diff --git a/library/ssl_ciphersuites.c b/library/ssl_ciphersuites.c
index 6089ca8..fdd7348 100644
--- a/library/ssl_ciphersuites.c
+++ b/library/ssl_ciphersuites.c
@@ -844,14 +844,12 @@
         size_t i;
         size_t max = sizeof(supported_ciphersuites) / sizeof(int);
 
-        memset( supported_ciphersuites, 0x00, sizeof(supported_ciphersuites) );
-
-        /* Leave room for a final 0 */
         for( i = 0; i < max - 1 && p[i] != 0; i++ )
         {
             if( ssl_ciphersuite_from_id( p[i] ) != NULL )
                 *(q++) = p[i];
         }
+        *q = 0;
 
         supported_init = 1;
     }