rgw: add location when data in another region.

When the bucket of requested is in another region, Add location header
in response, so client can follow that to get data.

Signed-off-by: VRan Liu <gliuwr@gmail.com>
Merge pull request #2801 from CzBiX/permanent-location

rgw: add location when data in another region.

Reviewed-by: Yehuda Sadeh <yehuda@redhat.com>