mqtt api: minior bugfix

opencv-motion-detect/mqtt_helper.hpp

@@ -385,7 +385,7 @@ void my_on_msg1(MqttHelper *hlp, const void * const data, int len, string topic)
     memcpy(msg.data(), data, len);
     msg.data()[len] = 0;
     spdlog::info("I1 recv on {}: {}", topic, msg);
-    (*hlp)[to_string(atoi(topic.data()) + 1)]("hello ack", 10);
+    (*hlp)[to_string(atoi(topic.data()) + 1)]("hello ack1", 11);
 }
 
 void my_on_msg2(MqttHelper *hlp, const void * const data, int len, string topic){
@@ -394,7 +394,7 @@ void my_on_msg2(MqttHelper *hlp, const void * const data, int len, string topic)
     memcpy(msg.data(), data, len);
     msg.data()[len] = 0;
     spdlog::info("I2 recv on {}: {}", topic, msg);
-    (*hlp)[to_string(atoi(topic.data()) + 1)]("hello ack", 10);
+    (*hlp)[to_string(atoi(topic.data()) + 1)]("hello ack2", 11);
 }
 
 int main(){
@@ -426,7 +426,6 @@ int main(){
     }
 
     this_thread::sleep_for(chrono::seconds(2));
-    
     return 0;
 }