Allow users to use swift out of the box

When you assign a user to project in Horizon, this change allows
that user to use swift without further action.

Notes:

- This change is related to https://review.openstack.org/#/c/92388/
  in tripleo-incubator but can merge independently.
- Once this change merges, a logical follow up is to remove
  the creation of the swiftoperator role in tripleo-incubator
- However, in *this* change, we setup tempest to allow a
  subsequent removal of swiftoperator (the motivation is to
  reduce the number of roles for admins to manage)

Change-Id: Ib45e915eed923f7b8360593eb732e09b9683e77f
Merge "Allow users to use swift out of the box"