Don't try to close the dome if already closed after bad weather (#74)

According to isClosed docs: "It is called also outside of the closing sequence, to check if dome is closed when bad weather arrives."

Right now, I get a lot of "closeDomeWeather: domeCloseStart" spam in the logs when it's daytime and the weather station reports bad weather.

This commit avoids all that spam and will only log if it's not closed.

lib/rts2/dome.cpp

@@ -357,7 +357,9 @@ int Dome::closeDomeWeather ()
 	{
 		if (domeAutoClose == NULL || domeAutoClose->getValueBool () == true)
 		{
-			logStream (MESSAGE_DEBUG) << "closeDomeWeather: domeCloseStart" << sendLog;
+			if (isClosed() != -2) {
+				logStream(MESSAGE_DEBUG) << "closeDomeWeather: domeCloseStart" << sendLog;
+			}
 			ret = domeCloseStart ();
 		}
 		setMasterStandby ();