Like 02d0063b - pristine copy from omnibus-gitlab 8.6.5+ce.0-0-g342f8be

Changes are in:

    - gitlab.yml.erb

      * + ldap.sync_time    (we do not use LDAP)
      * artifacts.storage_path -> artifacts.path

    - nginx.conf.erb

      * proxy cache can be configured (gitlab defaults to up to 1GB
        on-disk cache)

            https://gitlab.com/gitlab-org/omnibus-gitlab/commit/8b91c071

        This cache was introduced by upstream instead of accepting
        https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/17

        For raw blobs downloading the cache is activated essentially for
        public projects only (only for them cache-control is public)

            https://gitlab.com/gitlab-org/gitlab-ce/commit/fc90d9e5#a587159e3f053514fa2a9a4fa9a9cb56e6928df0_155_157

        The cache is not very effective, and under load can do more harm
        than good:

            https://gitlab.com/gitlab-org/gitlab-workhorse/merge_requests/17#note_4082683

        Since we have fast raw blobs serving by our gitlab-workhorse
        patches, and caches on frontends, for this cache, offhand we are
        not very interested.

    - nginx-gitlab-http.conf.erb

      * nginx can connect to gitlab-workhorse not via unix://  (we
        always use unix://)

      * HTTP/2 support can be disabled (we are going to always support HTTP/2)

      * All static content (except 404,422,500,502) is now served by
        gitlab-workhorse (under nginx), not nginx directly

        https://gitlab.com/gitlab-org/omnibus-gitlab/commit/48dce4ec

The following files stay the same:

    - database.yml.erb
    - gitconfig.erb
    - gitlab-rails-config.ru.erb
    - gitlab-shell-config.yml.erb
    - rack_attack.rb.erb
    - resque.yml.erb
    - smtp_settings.rb.erb
    - unicorn.rb.erb