gerrit.py: Support `.googlesource.com` credentials

The scripts currently check that the requested domain exactly matches
one of the domains in the user's `.gitcookies` file, which causes
a "Cannot find the domain" error if the user's credentials are for all
of `googlesource.com`.

Change-Id: Ifed117e7d76c8678558720db1d518d59d986521d
1 file changed