Project purge would delete the servers and volumes for the project the
user is currently authenticated for, regardless of the --project flag.
Note: This change means that no server at all will be deleted if the
logged in user doesn't have the get_all_tenants permission set in the
Nova policy (default: admin_api). This doesn't appear to be an issue
with Cinder as the default rule appears to be admin_or_owner.
Change-Id: If1c54e24e1482438b81c3c32fd5fc9fdd7a7be04
Story: 1747988
Task: 13854
1b66ad9067