Make existing commit notification config work with the GitLab move

In GitLab we moved all repositories into groups, so for example 'breeze'
is now received as 'plasma/breeze' in the commit notification email.
However, the existing notifications.cfg file has regexes that expect to
match a lone 'breeze' in the repository name.

Instead of changing every regex in the configuration, make the notification
script try to match the regex against both 'plasma/breeze' and 'breeze'.