The swift_bytes param is removed from the content-type
in the proxy object controller, so the SLO unit tests should
not be registering GET responses with FakeSwift that have
swift_bytes appended to the content-type.
Nor should submanifest segment dicts have swift_bytes appended to
their content-type values.
Also adds a test for the object controller and container server
handling of SLO swift_bytes.
Change-Id: Icf9bd87eee25002c8d9728b16e60c8347060f320
7b706926a8