Don't create new groups for system ones

A Gerrit bug[1] allowed manage_projects to create a Gerrit
internal group with the same name as a system group
('Registered Users').  This happened after upgrading to
Gerrit 2.11 because there are existing projects with 'Registered
Users' in acls config files.  Even though Gerrit shouldn't allow
creation of a group with the same name as a system group,
manage_projects shouldn't even attempt to do it.

This change prevents manage_projecsts from creating
groups with the same name as Gerrit system groups.  It
will also add correct entries to group files for system groups.
Below is the group file entries that Gerrit expects for
system groups:

global:Anonymous-Users                  	Anonymous Users
global:Change-Owner                     	Change Owner
global:Project-Owners                   	Project Owners
global:Registered-Users                 	Registered Users

For backward compatibility, the existing group UUID will be returned
if one is found in the database.

[1] https://code.google.com/p/gerrit/issues/detail?id=3831

Change-Id: I17d6e1a5553f98ff910480d41a2ac7b3a2522809
1 file changed