Merge BadRequest tests of "get console output" API

In test_console_output, there are BadRequest tests of "get console output".
Most parts of them are duplicated.
This patch merges them for the readability and clarifying their purposes.

Change-Id: Ia83cf1b77a7a185a195286234d7f943d0ca7537f
libvirt: parse disk backing chains from domain XML

Add support for parsing <backingStore> XML elements in the libvirt
domain XML description for disks.

This is being added to libvirt in order to support blockjob operations
for network-attached disks.

Implements: blueprint libvirt-volume-snap-network-disk

Change-Id: I370c9e8d6a1b1f66e385f009f897816f2e705a36
Use v1 as default for cinder_catalog_info

In c5402ef4fc509047d513a715a1c14e9b4ba9674f we recently
added support for the Cinder v2 client. This change modified
the default value of the cinder_catalog_info config such
that an end user who was previously using the Cinder V1
API via the default config setting (by not setting it) would
have a broken Nova -> cinder configuration upon upgrade.

We should hold off on changing the default cinder_catalog_info
for one release to allow for proper deprecation.

Change-Id: I040b2c87ad0a2be92f31264e293794d97c27c965
Closes-bug: #1354499
Consistently use jsonutils instead of specific implementation

jsonutils have several benefits in comparison to pure json
implementation, like enabling C boosted encoders and decoders for
Python2.6 by using simplejson when available.

Change-Id: I24d0cd442e8d9d89fac50e43fc97f7bb4a293c3d
Closes-Bug: 1329496
Added hacking check for jsonutils

jsonutils provides some additional features in comparison to pure json
or simplejson modules. For example, on Python 2.6, it automatically
switches to simplejson that provides significant performance boost.

So let's enforce usage of the module in replacement to stdlib json.

Change-Id: I86ed6cd3316dd4da5e1b10b36a3ddba3739316d3
Drop instance_group_metadata from the database

This completes the instance_group metadataectomy started in the previous
patch. Per recent discussions, this decouples the code change from the
actual schema change, allowing them to (potentially) be run at different
times.

Change-Id: I6c3ff35f6e90fbed8b1fd727eb3b0b0ee140abc4
Merge "libvirt: parse disk backing chains from domain XML"
Merge "Consistently use jsonutils instead of specific implementation"
Merge "Added hacking check for jsonutils"
Merge "Use v1 as default for cinder_catalog_info"
Merge "Drop instance_group_metadata from the database"
Merge "Merge BadRequest tests of "get console output" API"