Ignore the default quota values

The default Quota values are just values from config file,
and they are usually different at ever cloud provider.

In the API compatibility perspective the values are not
important, but the keys presence is important.

The other option would be, adding the expected response to the
tempest config.

The test_get_updated_quotas test case also got a dedicated tenant.

Fixing bug 1130461
Change-Id: I50204dc7955d68491ad63f239c42fb47591a0be7
Simplify whitebox/manager

* Allow the generic resource deletion (thing.delete) to
operate on resources allocated in the setUpClass-es too.

* test_images_whitebox.py is using the python
  client libraries as the scenario tests.

* Remove the not used part of the tempest/manager.py

Change-Id: I980a70d22dc7a3a65a26a8197c7888b125eb3b05
Merge "Simplify whitebox/manager"
Merge "Ignore the default quota values"