Add a timeout to discovery if already have results
Add a timeout to discovery if already have results

 * If one provider gives us results on a domain, and other providers
   take a really long time, then ignore the tardy fellows.

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