Remove handling for client status races

Now that we guarantee that resources are UPDATE_IN_PROGRESS before the
stack update call returns for legacy stacks (this was already true for
convergence stacks), there is no need to have special handling to check the
updated_time in functional tests.

Change-Id: I1ebf38285746a090660044ffdb854e98b5f0dba0
Depends-On: https://review.openstack.org/589172
Story: #1669608
Task: 23349
2 files changed