Fix compiler warning

ws/IXRedisClient.cpp

@@ -242,7 +242,7 @@ namespace ix
         return true;
     }
 
-    bool RedisClient::stop()
+    void RedisClient::stop()
     {
         _stop = true;
     }

ws/IXRedisClient.h

@@ -32,7 +32,7 @@ namespace ix
                        const OnRedisSubscribeResponseCallback& responseCallback,
                        const OnRedisSubscribeCallback& callback);
 
-        bool stop();
+        void stop();
 
     private:
         std::string writeString(const std::string& str);