Correctly set adapter to response.connection

The response.connection should be the adapter that the request went
through. This is important in some situations (requests-kerberos) where
the connection is reused by the auth plugin to send additional requests.

Change-Id: I87bf996e2edbfb29eba9b4000d976a49cbf6c8cc
Closes-Bug: #1358903
Merge "Correctly set adapter to response.connection"