Merge branch 'backup_ci_rm' into 'master'

Remove note on backing up GitLab CI as a separate service

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/13405

See merge request !2803

doc/raketasks/backup_restore.md

@@ -18,8 +18,6 @@ for two-factor authentication. If you restore a GitLab backup without
 restoring the database encryption key, users who have two-factor
 authentication enabled will lose access to your GitLab server.
 
-If you are interested in GitLab CI backup please follow to the [CI backup documentation](https://gitlab.com/gitlab-org/gitlab-ci/blob/master/doc/raketasks/backup_restore.md)*
-
 ```
 # use this command if you've installed GitLab with the Omnibus package
 sudo gitlab-rake gitlab:backup:create