fix for cc7

The packages specified in the Ks file and its order might have affected cc7.

Possibly related to:

# Required for CentOS 7.x due to no blscfg: https://bugzilla.redhat.com/show_bug.cgi?id=1570991#c6

Making this adjustment for CC7 does the trick, not required for C8.

Still unknown how images were working without oz changes, downgrading its package did not produce working images, as ImageFactory was unable to boot in UEFI mode, as code is obviously not adapted.