Removed the vendored git-lfs and the GitLfs build flag

AFAICS all git-annex builds are using the git-lfs library not the vendored
copy.

Debian stable does have a too old haskell-git-lfs package to be able to
build git-annex from source, but there is not currently a backport of a
recent git-annex to Debian stable. And if they update the backport at some
point, they should be able to backport the library too.

Sponsored-by: Svenne Krap on Patreon

Remote/GitLFS.hs

@@ -7,7 +7,6 @@
 
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RankNTypes #-}
-{-# LANGUAGE CPP #-}
 
 module Remote.GitLFS (remote, gen, configKnownUrl) where
 
@@ -44,12 +43,7 @@ import Logs.Remote
 import Logs.RemoteState
 import qualified Git.Config
 
-#ifdef WITH_GIT_LFS
 import qualified Network.GitLFS as LFS
-#else
-import qualified Utility.GitLFS as LFS
-#endif
-
 import Control.Concurrent.STM
 import Data.String
 import Network.HTTP.Types