Let resource_tracker report right migration status

A shutoff instance can be resized, but resource_tracker only think
active instance is in migration state. This patch let it report
right migration status.

Closes-Bug: #1247610

Change-Id: Ic6ce9c7d8fdecaf812831eb302186133f0ee71b1
Fix limits v3 follow API v3 rules

* Add expected_errors decorator.
* Remove 'absolute_limit' from response, that already return by
extension quota_sets. And update api samples.

Partially implements bp nova-v3-api

Change-Id: Iea3ff494b8abed77fdc4b9e5e552784ed3733c34
Use 400 instead of 422 for invalid input in v3 servers core

We return 400 when input is invalid for v3 api. This patch fix
this case for servers core.

DocImpact

Change-Id: If802d4dcba6ed25f7e9cb9d568a3ffd78f0f6c68
Closes-Bug: 1251538
VMware: Always upload a snapshot as a preallocated disk

Currently, a snapshot operation always produces a preallocated
disk type. When the snapshot is uploaded to glance, the source
image metadata is uploaded with the new snapshot and then some
of the metadata properties are updated. The update doesn't
include the disk_type property, this can be problematic. If
the original image has a sparse disk type and a snapshot is
taken, then the snapshot which is a preallocated disk type is
uploaded to glance with the disk_type property set to sparse,
which creates a disk type mismatch and causes errors when a vm
is spawned from that snapshot. This patch addresses the issue
by correcting the image metadata used when uploading a snapshot
to glance.

Also, the image_upload function in vmwareapi/fake.py has been
modified to address the change. Any function call to
image_upload (from the unit tests) will assert that the
metadata for the image to be uploaded must have the disk_type
value to be preallocated.

Closes-Bug: 1247296
Change-Id: I71cfa8d4d1eb7911abb489153292fb0d1e614765
Clean up how test env variables are parsed

Oslo and cookiecutter and other projects were using
variable to parse test environment vaiables. Let us
do this in Nova

This is copied from 739627bf79619f8 Use cleaner version from
cookiecutter OpenStack template

Change-Id: I4c2b4072981985e7632fc775ffc98216fbfc0508
Merge "Fix limits v3 follow API v3 rules"
Merge "VMware: Always upload a snapshot as a preallocated disk"
Merge "Clean up how test env variables are parsed"
Merge "Let resource_tracker report right migration status"
Merge "Use 400 instead of 422 for invalid input in v3 servers core"