Read config from .zuul.yaml or zuul.yaml

Repos which exist only for the purpose of providing Zuul configuration
and jobs should be able to use the zuul.yaml file even if they are
untrusted.  Therefore, read both filenames from both kinds of repos.

Change-Id: Ib24cbb3a4c8752aa61868c2dbca63141cb35ff51
1 file changed