Function rgblk_free can only deal with one resource group at a time, so
pass that resource group is as a parameter. Several of the callers
already have the resource group at hand, so we only need additional
lookup code in a few places.
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> Signed-off-by: Bob Peterson <rpeterso@redhat.com> Reviewed-by: Steven Whitehouse <swhiteho@redhat.com>