add multi-delete support for compute/image/net/volume

This is part1, add support for these objects:
compute.server
imagev1.image
imagev2.image
network.network
volume.volume
volume.backup
volume.snapshot

Closes-Bug: #1400597
Change-Id: Ice21fee85203a8a55417e0ead8b509b8fd6705c1
add multi-delete support for identity

This is part2. Add support for these objects:
identity.project(v2.0)
identity.role(v2.0)
identity.user(v2.0)
identity.project(v3)
identity.role(v3)
identity.user(v3)
identity.group(v3)

Closes-Bug: #1400597
Change-Id: I270434d657cf4ddc23c3aba2c704d6ef184b0dbc
Merge "add multi-delete support for compute/image/net/volume"