allow maat_json.json has no compile/g2c/g2c table

tools/maat_redis_tool.cpp

@@ -26,6 +26,7 @@ void maat_tool_print_usage(void)
 	printf("\t-p [port], redis port, 6379 as default.\n");
 	printf("\t-n [db], redis db, 0 as default.\n");
 	printf("\t-d [dir], dump rules from redis to [dir], %s as default.\n", redis_dump_dir);
+    printf("\t-u [dir], flush redis and upload full rules to redis, confirm the risk before proceeding\n");
 	printf("\t-v [version], dump specific [version] from redis, dump latest version as default.\n");
 	printf("\t-j [payload.json], add or delete rules as maat json. Must have field compile_table field, and plugin table's valid flag must be in the last column.\n");
 	printf("\t-t [timeout], timeout config after t seconds, default is 0 which means never timeout.\n");