Fix ProjectWiki#http_url_to_repo signature
requested to merge 29685-wrong-number-of-arguments-calling-http_url_to_repo-on-cloning-project-wikis-ee into master
EE MR for https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/10079.
New Gitlab::UrlSanitizer.http_credentials_for_user method responsible for generating a credentials hash from a user.