The image metadata construction code allows for subvariant to be
set in the image config dict, but checks.py doesn't expect it;
fix that. Also, when a subvariant is set, use it in the image
name template rather than the variant; otherwise you can't
build more than one subvariant in any variant (they will have
identical names, which isn't alllowed).
Signed-off-by: Adam Williamson <awilliam@redhat.com>
(cherry picked from commit 391a5eaed5198e5ee2941dac4ae43a2fe057eedd)
a0a155ebcd