Fix Instance Details error when using Cinder V2

If you're using cinder V2 API you will get an error for instance details view.
The function 'instance_volumes_list' is called by the detail view of an instance
and try to get from 'display_name'. Since Cinder v2 it's changed to 'name'.

Change-Id: I20de0b8e6c263fc306e1475ddd40b4156e828bf1
Closes-Bug: #1386727
Related-Bug: #1226944
Co-Authored-By: Julie Pichon <jpichon@redhat.com>
Merge "Fix Instance Details error when using Cinder V2"