Merge branch 'master' into 'master'

Enhance the LDAP group synchronization

The response of our company's LDAP for a group looks like this:
```
dn: <dn-of-the-selected-group>
cn: <name-of-the-selected-group>
submember: uid=<username-of-a-submember>
member: uid=<username-of-a-member>
```
So the current implementation of the LDAP group synchronization in GitLab can't find any registered user in such a group. This merge request will fix this.

This is a "copy" of this merge request https://gitlab.com/subscribers/gitlab-ee/merge_requests/27 that was in the wrong repository.

See merge request !1

CHANGELOG-EE

 v 7.12 (Unreleased)
   - Fix error when viewing merge request with a commit that includes "Closes #<issue id>".
+  - Enhance LDAP group synchronization to check also for member attributes that only contain "uid=<username>"
+  - Enhance LDAP group synchronization to check also for submember attributes
 
 v 7.11.2
   - Fixed license upload and verification mechanism

lib/gitlab/ldap/group.rb

@@ -42,13 +42,17 @@ module Gitlab
           member_uids.any? { |member_uid| member_uid.downcase == user_uid }
         elsif member_dns.any? { |member_dn| member_dn.downcase == user_dn }
           true
+        elsif member_dns.any? { |member_dn| member_dn.downcase == "uid=" + user_uid }
+          true
         elsif adapter.config.active_directory
           adapter.dn_matches_filter?(user.dn, active_directory_recursive_memberof_filter)
         end
       end
 
       def member_dns
-        if entry.respond_to? :member
+        if (entry.respond_to? :member) && (entry.respond_to? :submember)
+          entry.member + entry.submember
+        elsif entry.respond_to? :member
           entry.member
         elsif entry.respond_to? :uniquemember
           entry.uniquemember