allow directory remotes to be in different locations

Two machines might have access to the same directory remote on different
paths, so don't include the path in its persistent config, instead use
the git config to record it.

Remote/S3real.hs

@@ -88,7 +88,7 @@ s3Setup u c = do
 				Right _ -> return ()
 				Left err -> error $ prettyReqError err
 
-	gitConfigSpecialRemote "s3" u fullconfig
+	gitConfigSpecialRemote u fullconfig "s3" "true"
 	return fullconfig
 	where
 		remotename = fromJust (M.lookup "name" c)