Actions that use GitLab user fail with some hook workflows

ZD Reference: https://gitlab.zendesk.com/agent/tickets/27208

Basically, having a custom hooks that verifies the identity of commiters based on either name or email fails when using UI tools such as the "Rebase Branch" button, this is due to the fact that the git_user has a git_user_email value that doesn't match any of the DB users.

We have a project that we're trying to use the "rebase" button and it appears nothing happens. We looked at the logs and found:

June 15, 2016 14:20 -> ERROR -> Failed to push rebased branch: 
June 15, 2016 14:20 -> ERROR -> remote: GitLab: Committer 'gitlab@xxx.yyy' is not a member of team XX /var/opt/gitlab/git-data/repositories/xxxxxxxx/xxxxxxxx.git ! [remote rejected] xxxxxxxx/xxxxxxxx -> xxxxxxxx/xxxxxxxx (pre-receive hook declined) error: failed to push some refs to '/var/opt/gitlab/git-data/repositories/xxxxxxxx/xxxxxxxx

The default "GitLab" user found on our server isn't a user in GitLab so our validation is failing (since it's turned on). Disabling this validation process isn't an option, either.

Looking at /etc/gitlab/gitlab.rb, there is a line that states:

# user['git_user_email'] = "gitlab@#{node['fqdn']}"

How can we handle this better? Any ideas?