If the default identity API version were to change
in devstack, the v2.0 tests would fail today,
resulting in a broken OSC gate.

Change-Id: Id634ea7e0fab9f3772383b5512ccac19f5119ac0

This change replaces in many identity functests the pattern:

 raw_resource = create_resource(...)
 check(raw_resource)
 self.addCleanup(delete_resource, ...)
 ...

by the pattern:

 raw_resource = create_resource(...)
 self.addCleanup(delete_resource, ...)
 check(raw_resource)
 ...

which ensures that cleanup is defined and called after the test even if
check(resource) fails.

Change-Id: I4da541b7552d06eaffafda446e389bb552422cda

This reverts commit 5032dbc8074d5133c6b71610cd57d3c8da07c9b9 based on [1].

[1] https://review.openstack.org/#/c/274703/

Change-Id: Ic10ef7c37d71e452fbc4bd36e28be79d669b4e3f

DevStack now uses identity v3 by default thus causing OSC to
only load openstack.identity.v3 commands. This prevents running
functional tests on openstack.identity.v2 commands. As a result,
this patch set skips all identity v2 functional tests to unblock
the gate.

Change-Id: I066187318be71792a966fa21226fab0d406c3758
Partial-Bug: #1539780

split test_identity.py into test_user.py, test_project, etc.
To make functional tests run repeatedly without raising
duplicated error, clean up resources before exiting each test case.

Change-Id: I8f31ccbd70f1cccdab8b3720aac179e2e399486d
Implements: blueprint identity-functional-tests