gitlab-ci: Use single if for manual job rules entry

I thought multiple ifs would all need to match, but looks like only the
last one (or either one?) does.

This should prevent a manual pipeline from getting created after merging
changes which can't affect the pipeline.

Reviewed-by: Eric Engestrom <eric@engestrom.ch>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3474>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3474>
1 file changed