Except when running on the pre-upgrade release in the upgrade
tests (where GPG check should always be OK).
Currently we always need to use --nogpgcheck on Rawhide, and we
must also use it on Branched prior to the Bodhi activation
point. At present we don't really have any simple way to know
when the Bodhi activation point has kicked in. We could assume
that it's safe to do GPG checking for 'candidate' (not nightly)
composes, but even that isn't 100% safe and isn't really the
*right* thing to do. So I think for now it's best to just always
use --nogpgcheck , until we come up with a decent way to check
for Bodhi enablement, or releng figures things out so we can
rely on packages being signed in Rawhide and in Branched before
Bodhi enablement.