CDRIVER-3336 Uninitialised BSON reply on error

Author: bazile-clyde

src/libmongoc/src/mongoc/mongoc-cluster.c

@@ -1896,6 +1896,7 @@ mongoc_cluster_stream_for_server (mongoc_cluster_t *cluster,
    BSON_ASSERT (server_id);
 
    if (cs && cs->server_id && cs->server_id != server_id) {
+      _mongoc_bson_init_if_set (reply);
       bson_set_error (error,
                       MONGOC_ERROR_COMMAND,
                       MONGOC_ERROR_SERVER_SELECTION_INVALID_ID,

src/libmongoc/tests/test-mongoc-transactions.c

@@ -957,6 +957,7 @@ test_selected_server_is_pinned_to_mongos (void *ctx)
    ASSERT_OR_PRINT (r, error);
 
    bson_destroy (insert_opts);
+   bson_destroy (&reply);
    mongoc_collection_destroy (coll);
    mongoc_database_destroy (db);
    mongoc_session_opts_destroy (session_opts);