images: Update rhel-7-6 image
images: Update rhel-7-6 image

Closes #11762

cockpit-project/cockpit,deryni/cockpit,moraleslazaro/cockpit,deryni/cockpit,mvollmer/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,garrett/cockpit,cockpit-project/cockpit,moraleslazaro/cockpit,deryni/cockpit,garrett/cockpit,martinpitt/cockpit,mvollmer/cockpit,garrett/cockpit,deryni/cockpit,cockpituous/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,cockpituous/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,cockpituous/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,deryni/cockpit,cockpituous/cockpit,deryni/cockpit,moraleslazaro/cockpit,moraleslazaro/cockpit,martinpitt/cockpit,garrett/cockpit,deryni/cockpit,garrett/cockpit,moraleslazaro/cockpit,cockpituous/cockpit