Compression/tier capabilities for Storwize/SVC.

Compression and tiering support were not exported as capabilities,
and are important features.

Also fix a couple bugs introduced by
https://review.openstack.org/#/c/23830/

Change-Id: I41c304d0da89a050c0345b930b3f45741214b425
Fixes: bug 1146341
Fixed: bug 1155071
Merge "Compression/tier capabilities for Storwize/SVC."