Minor update to fix track on upgrade test

This should fix "Upgrading keystone to 2022.2/stable" resulting
in 'no releases found for channel "2022.2/stable"'.

Instead, keystone should be upgraded to zed/stable.

zaza/openstack/charm_tests/charm_upgrade/tests.py

@@ -52,7 +52,7 @@ def test_200_run_charm_upgrade(self):
                 os_version, os_codename = (
                     upgrade_utils.determine_next_openstack_release(
                         charm_track))
-                if os_versions.CompareOpenStack(os_codename) >= 'zed':
+                if os_versions.CompareOpenStack(os_codename) > 'zed':
                     new_charm_track = os_version
                 else:
                     new_charm_track = os_codename