Fixes Tempest XML test failures for Cisco N1kv plugin

Renamed N1kv_profile class to N1kv.
Modified N1kv attribute extension class to fix XML namespace issues.

Change-Id: I29b541730fc95c5e16667b64efd180be31e25b17
Closes-Bug: #1282352
Merge "Fixes Tempest XML test failures for Cisco N1kv plugin"