Fix git group detection for gitolite ssh user.

Created by: VonC

The tasks gitlab:env:info mixes user and group, and presume as a group 'git'. However, gitolite group name can be anything.

That patch add the git group name in the config, and check gitolite.ssh_user group against git.group (which defaults to 'git', as before this patch, if undefined).

M config/gitlab.yml.example: Add 'group' in 'git' section Mention default value for the two extra settings M lib/tasks/gitlab/check.rake: Check that gitolite.ssh_user group is the one defined in git.group. Make sure to default to 'git' as the expected group if said group is undefined in the config. Note: uses a more complete regexp for the group detection (the group can start, end or be in the middle or the list of groups of gitolite.ssh_user)