MXS-1775 Monitoring function named consistently

The main monitoring function now has the same name in all
monitors (except MariaDBMonitor) and is a member function.

server/modules/monitor/mmmon/mmmon.hh

@@ -40,6 +40,8 @@ private:
 
     MXS_MONITORED_SERVER *get_current_master();
 
+    void update_server_status(MXS_MONITORED_SERVER *database);
+
     bool has_sufficient_permissions() const;
     void configure(const MXS_CONFIG_PARAMETER* params);
     void tick();