test: Make check-login nondestructive
test: Make check-login nondestructive

Revert changes to other config files and rename instead of remove
binaries.

Also clean up user creation/removal a bit, as MachineCase.setUp() now
does that for us.

Part of issue #13481
Closes #13584

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