Add the option for all users to create containers in Swift

* Create "swift_allow_all_users" var - default to False
* Adjust swift-proxy-server.conf based on this value
* If true add _member_ to allowed users.

Fixes #610
Setup glance to use swift as a backend

* Add the swiftoperator role
* Add the swiftoperator role to the glance user when glance is using swift

Fixes #610
Merge pull request #625 from andymcc/swift_user_perms

Swift user permissions changes.