POST v2.0/images (cont...)

Implements a new test: register image and add additional property to it.
 - Added a register image and add additional property test to post images test scenario.
 - Corrected the test type and changed it from 'negative' to 'positive'.

Refactors 'test_register_image_with_compulsory_properties' test.
 - Corrected the container_format and disk_format data in
   'test_register_image_with_compulsory_properties' test.

Change-Id: I3f7eed02454c1a93424b233233d90810aa1e90ea
Removing rbac tests from cloudroast

*Removed rbac package
*Removed rbac get_images_schema test template module

Change-Id: I4c6a7dd14bc5037d2c3c2829df7b8695c1ba9d4a
Merge "POST v2.0/images (cont...)"
Merge "Removing rbac tests from cloudroast"