Properly pass comparator to priority queue
Properly pass comparator to priority queue

There was a bug before where our Nonblocking.Mailbox's priority queue
wasn't actually being created correctly.  This fixes that.  Sounds like
this might affect lots of things, especially the order in which the
background fetcher syncs folders.

jimbonator/geary,aatishnn/geary,jimbonator/geary,martinra/geary,aatishnn/geary,jimbonator/geary,MohamedIM/geary-unofficial,geekvigilante/geary,glebihan/geary,tshikaboom/geary,AtticHacker/geary,emersion/geary,tshikaboom/geary,rschroll/geary,githubnemo/geary,mjog/geary,AtticHacker/geary,kyoushuu/geary,robol/geary,martinra/geary,kyoushuu/geary,aatishnn/geary,glebihan/geary,rschroll/geary,emersion/geary,glebihan/geary,tshikaboom/geary,mjog/geary,mjog/geary,AtticHacker/geary,kpiwko/geary,githubnemo/geary,abn/geary,martinra/geary,mpdeimos/geary,emersion/geary,robol/geary,githubnemo/geary,robol/geary