hGetContents closes handle

hGetContents doesn't create Handle and therefore it is not obvious why it closes it. Handle is closed on a bracket.

```
data GitObject
= GitObject
{ gobHash :: !(Digest SHA1State)
, gobOrigin :: !FilePath
}
deriving (Show, Eq)

mkGitObject :: PhoenixM m => FilePath -> m (Maybe GitObject)
mkGitObject fp = do
s <- asks inHandlesSem
U.bracket_ (U.waitQSem s) (U.signalQSem s) $
U.withBinaryFile fp U.ReadMode $ \inH -> do
magicBs <- hGet inH 2
if zlibP magicBs
then do
!headerBs <- (magicBs <>) <$> hGet inH 10
(`U.catch` skipCorruptedFile inH) $ do
if gitObjectP $ Z.decompress (toLazy headerBs)
then do
!goh <- sha1 . Z.decompress . (toLazy headerBs <>) <$> hGetContents inH
pure . Just $ GitObject goh fp
else pure Nothing
else pure Nothing
where
skipCorruptedFile inH (e :: Z.DecompressError) =
case e of
Z.TruncatedInput -> do
fsz <- liftIO $ U.hFileSize inH
```