Merge pull request #811 from PX4/mavlink_sys_status_fix

mavlink: publish SYS_STATUS at constant rate

src/modules/mavlink/mavlink_messages.cpp

@@ -262,7 +262,7 @@ protected:
 
 	void send(const hrt_abstime t)
 	{
-		if (status_sub->update(t)) {
+		status_sub->update(t);
 		mavlink_msg_sys_status_send(_channel,
 						status->onboard_control_sensors_present,
 						status->onboard_control_sensors_enabled,
@@ -278,7 +278,6 @@ protected:
 						status->errors_count3,
 						status->errors_count4);
 	}
-	}
 };