CComponentsTimer: exec OnTimer cleanup after stopped thread

Users reported about crashes, but I could not verify them by myself.

Supplement to: c0fe5d2402

src/gui/components/cc_timer.cpp

@@ -143,10 +143,12 @@ bool CComponentsTimer::startTimer()
 bool CComponentsTimer::stopTimer()
 {
 	tm_enable = false;
-	OnTimer.clear();
 	stopThread();
-	if(tm_thread == 0)
+	if(tm_thread == 0){
+		if (!OnTimer.empty())
+			OnTimer.clear();
 		return true;
+	}
 
 	return false;
 }