bots: Stop testing obsolete rhel-7* images on master
bots: Stop testing obsolete rhel-7* images on master

master does not support RHEL 7 builds any more, so don't trigger these
tests on openshift or ipa images any more.

Closes #12347
deryni/cockpit,cockpituous/cockpit,mvollmer/cockpit,deryni/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,deryni/cockpit,garrett/cockpit,garrett/cockpit,moraleslazaro/cockpit,cockpituous/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpituous/cockpit,mvollmer/cockpit,deryni/cockpit,cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,mvollmer/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,deryni/cockpit,moraleslazaro/cockpit,garrett/cockpit,deryni/cockpit,martinpitt/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,cockpit-project/cockpit,cockpituous/cockpit,mvollmer/cockpit,cockpituous/cockpit,cockpit-project/cockpit,martinpitt/cockpit,garrett/cockpit