The types used in domaincommon.rng and secret.rng should be the same.

Move genericName to basictypes.rng, then drop redundant types now
that secret.rng uses basictypes.rng.
Signed-off-by: NJosh Durgin <josh.durgin@dreamhost.com>
Signed-off-by: NEric Blake <eblake@redhat.com>