Rename DeploymentViewSet 'archived' filter_field

[machristie]

This is to workaround a problem in coreapi where it doesn't handle very well when a form parameter and a query parameter have the same name. In this case it treats the DeploymentViewSet 'archived' form parameter as though it were a query parameter, which leads to a 404 and the deployment's archived value (nor any value) can be updated.

See https://github.com/CloudVE/cloudlaunch-cli/issues/4#issuecomment-376242683 for more information.

cloudlaunch-ui will need to be updated likewise.