Merge branch 'jk/fetch-quick-tag-following'

When fetching from a remote that has many tags that are irrelevant to branches we are following, we used to waste way too many cycles when checking if the object pointed at by a tag (that we are not going to fetch!) exists in our repository too carefully. * jk/fetch-quick-tag-following: fetch: use "quick" has_sha1_file for tag following