Allow multiple volume delete from cli like Cinder

In cinder project, we can use cli like follow:
cinder delete xxx yyy zzz
But in nova, we can not use follow command:
nova volume-delete xxx yyy zzz

This patch will add a feature in nova to allow multiple volume
delete from cli like cinder.

Change-Id: I4dd182673e58406a57d30c572ec3116f9f4ce315
Closes-Bug: #1262061
Don't slugify() None names

If image has no name, human_id can't be built.
Also slugify raises ValueError if None argument passed.
It affects Docker images.

Closes-Bug: #1267429
Closes-Bug: #1267130
Change-Id: Ib975775b441917eef2a650049cee9991d10c50d7
Merge "Don't slugify() None names"
Merge "Allow multiple volume delete from cli like Cinder"