RBAC tests for key_name in response

Adds tests for os-keypairs that looks for "key_name" in the
response body from a call to list or show server. Also adds a
skip exception to test_keypairs_rbac if os-keypairs extension
is not enabled.

Implements bp:rbac-tests-for-key-name-in-response

Change-Id: I2dc5332bfd59ea7c7a0e4a32b69d94ccd19ffaac
2 files changed