prop224: HSdir set changed detection fails sometimes
Seems like our logic for detecting HSDir hash ring changes on the service-side is not 100% correct. That's function service_desc_hsdirs_changed()
and family.
David noticed that function thinking that the hsdir set changed when it actually didn't. That also happened right after a desc upload, which caused tor to order another upload instantly. Tor ended up doing two desc uploads in two seconds, which raced to the HSDirs and arrived there on the wrong order causing rev counter fails.
We don't know the culprit yet but David added some debug logs that should help us out here.