ws: Fix leak in test-kerberos test

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
agent: Fix erroneous warning when cockpit-agent exits

Fixes this message:

Source ID 1 was not found when attempting to remove it

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>
ws: Fix memory leak in cockpit_auth_session_login_async()

Closes #1299

Reviewed-by: Marius Vollmer <marius.vollmer@redhat.com>