bots: Always keep mock cache for Fedora images
bots: Always keep mock cache for Fedora images

Fedora 31 needs this cache, Fedora testing needs it so soon also
Fedora-30 will need it. I think it is just more maintainable to always
keep it.

Fixes #12836
Closes #12839

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