fixes #406

Fix segfault caused by referencing uninitialized pointer
in dispatcher module.

(cherry picked from commit b71f6de)

modules/dispatcher/dispatch.c

@@ -733,7 +733,7 @@ static ds_data_t* ds_load_data(ds_partition_t *partition)
 	str attrs;
 	str host;
 	int port, proto;
-	db_res_t * res;
+	db_res_t * res = NULL;
 	db_val_t * values;
 	db_row_t * rows;