Swift3 should be in the same region as all other cloud.
By default it has regaion name 'US'. It's ok for requests
that signed by version 1 of signature because they haven't
region information in request.
But S3 signature of version 4 protocol sends region name to server
and swift3 plugin checks that input region equals to internal.
And because all cloud lives with 'RegionOne' then swift3 fails
request because it has 'US' region name by default.

Change-Id: Icd817183b1a040110372a8ae5d73fd2f0ec5559c
Related-Bug: #1411078