use tenant:* as swift r/w acl

The related swift patch has been merged
(https://review.openstack.org/#/c/22820/), so Glance here could support
this multi tenant sharing feature.

fixed bug #1155389

Change-Id: I36dfc7bdae133149e38e8266666e70cc07490554
Merge "use tenant:* as swift r/w acl"