test: Clean obsolete centos-8-stream special case in TestLogin.testSELinuxRestrictedUser
test: Clean obsolete centos-8-stream special case in TestLogin.testSELinuxRestrictedUser

This got fixed in RHEL 8.4, and CentOS 8 has caught up.

martinpitt/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,martinpitt/cockpit,garrett/cockpit,garrett/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit,cockpit-project/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,mvollmer/cockpit,garrett/cockpit