Fix a potential memory leak found by find-mem-leak.cocci.
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index ac35289..4eae92f 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -4063,8 +4063,13 @@
     ssl->psk = polarssl_malloc( ssl->psk_len );
     ssl->psk_identity = polarssl_malloc( ssl->psk_identity_len );
 
-    if( ssl->psk == NULL || ssl->psk_identity == NULL )
+    if( ssl->psk == NULL )
         return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+    if( ssl->psk_identity == NULL )
+    {
+        polarssl_free( ssl->psk );
+        return( POLARSSL_ERR_SSL_MALLOC_FAILED );
+    }
 
     memcpy( ssl->psk, psk, ssl->psk_len );
     memcpy( ssl->psk_identity, psk_identity, ssl->psk_identity_len );