Remove Swift location/password from messages.

Updates several exceptions and log messages in the Swift backend
so that they don't include Swift location URI's which may contain
passwords when used in Swift single tenant mode.

Fixes LP Bug #1098962 (for Folsom).

Change-Id: Ia97a95ce6ed5d98a76515eea8817e309bcf0889a
Merge "Remove Swift location/password from messages." into stable/folsom