use new name for new format fsck db

The old db is cleaned up when a new incremental fsck is started.

The incremental fsck won't pick up where the old one left off, but I
consider this a minor enough thing that it can just be documented and
won't be a problem.

Database/Fsck.hs

@@ -44,6 +44,8 @@ Fscked
 |]
 
 {- The database is removed when starting a new incremental fsck pass.
+ -
+ - (The old fsck database used before v8 is also removed here.)
  -
  - This may fail, if other fsck processes are currently running using the
  - database. Removing the database in that situation would lead to crashes
@@ -52,8 +54,10 @@ Fscked
 newPass :: UUID -> Annex Bool
 newPass u = isJust <$> tryExclusiveLock (gitAnnexFsckDbLock u) go
   where
-	go = liftIO . void . tryIO . removeDirectoryRecursive
-		=<< fromRepo (gitAnnexFsckDbDir u)
+	go = do
+		removedb =<< fromRepo (gitAnnexFsckDbDir u)
+		removedb =<< fromRepo (gitAnnexFsckDbDirOld u)
+	removedb = liftIO . void . tryIO . removeDirectoryRecursive
 
 {- Opens the database, creating it if it doesn't exist yet. -}
 openDb :: UUID -> Annex FsckHandle