Fix cross policy versioning DELETE

In the object_versions section of proxy.controllers.obj's DELETE the
X-Storage-Policy-Index header was not being set on the correct request, which
ment you'd get a 404 when you tried to DELETE an object in a versioned
container.  The 404 was acctually coming from the request to cleanup the old
version after it had already been copied over the current version.

Change-Id: Ibbf57abf16bc38c02e5703113ce5a17fa2a7dae2
Merge "Fix cross policy versioning DELETE" into feature/ec