Cinder wasn't filtering the backups returned to backup list API

This has the side effect of return all backups in the system (regardless of
who created them) to the user. You should only see the backups created in your
current active project.

Fixes bug: 1169461

Change-Id: I121e8ed215b28f1b21e24b2104f8294039e09b48
Merge "Cinder wasn't filtering the backups returned to backup list API"