Change v3 flavor_rxtx to v2.1

This patch changes v3 flavor_rxtx API to v2.1 and makes v2
unit tests share between v2 and v2.1.

The differences between v2 and v3 are described on the wiki page
https://wiki.openstack.org/wiki/NovaAPIv2tov3.

Partially implements blueprint v2-on-v3-api

Change-Id: I0b79be078ff2b2ca682f1f061f40c81d4487c7de
Merge BadRequest tests of v2 quota_sets API

In test_quotas, there are BadRequest tests of v2 quota_sets API.
Most parts of them are duplicated.
This patch merges them for the readability and clarifying their purposes.

Change-Id: I4313b2a80819260e9363f457ba271689308b145f
Plumb NetworkRequest objects through conductor and compute RPC

This makes the conductor and compute RPC paths for building instances
support and use NetworkRequest objects, which gets this all the way
down to the compute managers.

Change-Id: Ia45e15896b80ae33533d77719dd23bbdf60a1945
Instance objects: fix indentation issue

Fixes a minor indetation issue.

Change-Id: Ifd1dbc9be51f60a4d4099c742d183918184768bf
Merge "Instance objects: fix indentation issue"
Merge "Plumb NetworkRequest objects through conductor and compute RPC"
Merge "Change v3 flavor_rxtx to v2.1"
Merge "Merge BadRequest tests of v2 quota_sets API"