Port deferredDelete API to v3 Part 2

Ports the deferredDelete extensions and the corresponding unittests
to the v3 framework.

Partially implements blueprint nova-v3-api

Change-Id: Idc847e1b3c9fb422043d3a919452d842c2c4c30b
Port AttachInterfaces API to v3 Part 2

This patch contains the changes required to adapt the AttachInterfaces
extension and the corresponding unittest to the v3 framework

Partially implements: bp v3-api-extension-versioning

Change-Id: I0f3d4da962323a318448634e762f7c31490f9298
Merge "Port deferredDelete API to v3 Part 2"
Merge remote-tracking branch 'm_src_repo/citrix-fixes' into build-temp