add support for fully automatic upgrades

The Upgrader avoids checking for upgrades on startup when it was just
upgraded. This avoids an upgrade loop if something goes wrong. One example
of something going wrong would be if the upgrade info file and the
distribution file get out of sync (or the distribution file is cached in
a proxy), so it thinks it has upgraded to a new version, but has really
not.

Assistant/Threads/UpgradeWatcher.hs

@@ -8,7 +8,7 @@
 {-# LANGUAGE CPP #-}
 
 module Assistant.Threads.UpgradeWatcher (
-	upgradWatcherThread
+	upgradeWatcherThread
 ) where
 
 import Assistant.Common
@@ -30,9 +30,9 @@ import qualified Data.Text as T
 data WatcherState = InStartupScan | Started | Upgrading
 	deriving (Eq)
 
-upgradWatcherThread :: UrlRenderer -> NamedThread
-upgradWatcherThread urlrenderer = namedThread "UpgradeWatcher" $ do
-	whenM (liftIO $ checkSuccessfulUpgrade) $
+upgradeWatcherThread :: UrlRenderer -> NamedThread
+upgradeWatcherThread urlrenderer = namedThread "UpgradeWatcher" $ do
+	whenM (liftIO checkSuccessfulUpgrade) $
 		showSuccessfulUpgrade urlrenderer
 	go =<< liftIO upgradeFlagFile
   where