Fix hacking check for service client

Tempest hacking check _common_service_clients_check()
still has the ignored_list_T110.txt file check but this
file was already deleted a long back
- https://review.opendev.org/c/openstack/tempest/+/568489

This fix the pep8 check for service client checks otherwise it
fail on finding the ignored_list_T110.txt file.

Change-Id: I6069d1c2f6368e768640ce69981241792ea81aac
1 file changed