The "release" flavour of this file points at per-release repositories,
including kmods_quarterly_Y; but at the point that releng/X.Y is
created and X.Y-BETA1 builds start, there is no kmods_quarterly_Y
repository since that can't be built until after releng/X.Y exists.
Introduce a "beta1" flavour of /etc/pkg/FreeBSD.conf which points at
the base_release_Y repository for FreeBSD-base but still points at the
(not minor-version-number-tagged) kmods_quarterly repository for
FreeBSD-kmods. This may result in BETA1 users getting kmods which
were not built on exactly the right tree, but that's better than
having pkg fail because it's pointing at a repository which doesn't
exist.
MFC after: 1 week