test: Fix check-packagekit to run on a persistent testbed
test: Fix check-packagekit to run on a persistent testbed

testRunningUpdate is destructive as it removes cockpit-ws, and there is
no way to reinstate the package after that. Move it to a new
`TestWsUpdate` class.

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