Add tests list the availability zone

* Admin user is allowed to both list and list detail
* Regular user is allowed to get list
* Regular user is not allowed to get list detail

Partially Implements: blueprint missing-tempest-tests

Change-Id: I9d23c6677dcf4f4ba57e90097baeca374031604d
Adding test_max_image_meta_exceed_limit

A negative test which verifies that server creation
with exceeding of absolute limit maxImageMeta is impossible

Change-Id: Iac3604fcb12a77a41cf822eeee2b9cd0ce2a0178
Remove skips in test server rescue

* Remove skips test_rescued_vm_add_remove_security_group
* Fixes two issues
    1. In remove_security_group pass self.sg_name instead of sg_id which was
        failing earlier.
    2. Before executing unrescue server operation, the server status seems to
       be active hence the bug 1126257. So adding a rescue operation at the
       start of the test to fix the bug

Fixes bug 1126257

Change-Id: Ie79b94b9cde0f35bb4ea5955bc284139d85123cb
Merge "Remove skips in test server rescue"
Merge "Adding test_max_image_meta_exceed_limit"
Merge "Add tests list the availability zone"