Tempest has moved their attr decorator to tempest.lib [0]. So now
that decortators.attr is a part of Tempest's stable library, we
should use it instead of testtools.testcase.attr, since it is
the standardized way of adding attributes to test cases in
Tempest.
This allows the possibility of doing:
@decorators.attr(type=['foo', 'bar'])
Rather than:
@testtools.testcase.attr('foo')
@testtools.testcase.attr('bar')
[0] https://review.openstack.org/#/c/456236/
Change-Id: I76c23e46e57dbdbbce046f1522ed5489e5ec9d1f
ee7dfac465