stream-ssl: Fix memory leak on error path.

The commit that this fixes is from 2009.

Reported-by: Kai-Wei Fan <fank@vmware.com>
Fixes: 9467fe6 ("Add SSL support to "stream" library and OVSDB.")
Signed-off-by: Ben Pfaff <blp@ovn.org>
Acked-by: Andy Zhou <azhou@ovn.org>

lib/stream-ssl.c

@@ -670,7 +670,7 @@ ssl_send(struct stream *stream, const void *buffer, size_t n)
         case EAGAIN:
             return n;
         default:
-            sslv->txbuf = NULL;
+            ssl_clear_txbuf(sslv);
             return -error;
         }
     }