Due to circular dependencies, we need to turn off the
test_create_too_many_instances quota test in order to
get the client for quota management to pass the check/gate.
See https://review.openstack.org/#/c/331813
This test should be re-enabled by the server part of the change:
https://review.openstack.org/#/c/331323
Partial implements: blueprint bp/quota-management
Change-Id: I57cf03b14b059a71a93a095250cf4da644b02cab