Put check for computer-ou option during Leave() in subclass
Put check for computer-ou option during Leave() in subclass

 * This is so it doesn't have to be reimplemented by each realm
   derived class.
 * A later commit will remove it from the derived classes.

https://bugs.freedesktop.org/show_bug.cgi?id=56021

freedesktop-unofficial-mirror/realmd__realmd,freedesktop-unofficial-mirror/realmd__realmd,freedesktop-unofficial-mirror/realmd__realmd,freedesktop-unofficial-mirror/realmd__realmd