fix all remaining -Wincomplete-uni-patterns warnings

A couple of these were probably actual bugs in edge cases. Most of the
changes I'm fine with. The fact that aeson's object returns sometihng
that we know will be an Object, but the type checker does not know is
kind of annoying.

Git/UnionMerge.hs

@@ -84,14 +84,16 @@ doMerge hashhandle ch differ repo streamer = do
  - a line suitable for update-index that union merges the two sides of the
  - diff. -}
 mergeFile :: S.ByteString -> RawFilePath -> HashObjectHandle -> CatFileHandle -> IO (Maybe L.ByteString)
-mergeFile info file hashhandle h = case filter (`notElem` nullShas) [Ref asha, Ref bsha] of
-	[] -> return Nothing
-	(sha:[]) -> use sha
-	shas -> use
-		=<< either return (hashBlob hashhandle . L8.unlines)
-		=<< calcMerge . zip shas <$> mapM getcontents shas
+mergeFile info file hashhandle h = case S8.words info of
+	[_colonmode, _bmode, asha, bsha, _status] -> 
+		case filter (`notElem` nullShas) [Ref asha, Ref bsha] of
+		[] -> return Nothing
+		(sha:[]) -> use sha
+		shas -> use
+			=<< either return (hashBlob hashhandle . L8.unlines)
+			=<< calcMerge . zip shas <$> mapM getcontents shas
+	_ -> return Nothing
   where
-	[_colonmode, _bmode, asha, bsha, _status] = S8.words info
 	use sha = return $ Just $
 		updateIndexLine sha TreeFile $ asTopFilePath file
 	-- Get file and split into lines to union merge.