CI: check-logs - add another exception

It was seen in [1] and some other occassions, possibly neutron was trying
to fetch token while keystone was being upgraded.

[1]: https://storage.bhs.cloud.ovh.net/v1/AUTH_dcaab5e32b234d56b626f72581e3644c/zuul_opendev_logs_ec2/665117/12/check/kolla-ansible-ubuntu-source-upgrade/ec2fc04/primary/logs/kolla/all-CRITICAL.txt

Change-Id: If8c569e1f7815520c84627671e3cbf275bed8ff9
(cherry picked from commit 661ca4d)

Author: mnasiadka

tests/check-logs.sh

@@ -30,6 +30,7 @@ function filter_out_expected_critical {
         # Sometimes we see this during shutdown (upgrade).
         # See: https://bugs.launchpad.net/neutron/+bug/1863579
         grep -v "WSREP has not yet prepared node for application use"
+        grep -v "Failed to fetch token data from identity server"
         ;;
     *)
         # We have to provide some pass-through consumer to avoid: