Improved display of errors when accessing a git http remote fails.

New error message:

  Remote foo not usable by git-annex; setting annex-ignore

  http://localhost/foo/config download failed: Configuration of annex.security.allowed-ip-addresses does not allow accessing address ::1

If git config parse fails, or the git config file is not available at the url,
a better error message for that is also shown.

This commit was sponsored by Mark Reidenbach on Patreon.

Annex/Url.hs

@@ -19,7 +19,6 @@ module Annex.Url (
 	download',
 	exists,
 	getUrlInfo,
-	U.downloadQuiet,
 	U.URLString,
 	U.UrlOptions(..),
 	U.UrlInfo(..),