fix some mixed space+tab indentation

This fixes all instances of " \t" in the code base. Most common case
seems to be after a "where" line; probably vim copied the two space layout
of that line.

Done as a background task while listening to episode 2 of the Type Theory
podcast.

Command/Fsck.hs

@@ -329,7 +329,7 @@ checkKeySizeOr bad key file = case Types.Key.keySize key of
 checkBackend :: Backend -> Key -> Maybe FilePath -> Annex Bool
 checkBackend backend key mfile = go =<< isDirect
   where
-  	go False = do
+	go False = do
 		content <- calcRepo $ gitAnnexLocation key
 		checkBackendOr badContent backend key content
 	go True = maybe nocheck checkdirect mfile