Enforce ordering of imports with H306.

For tests, this is mostly done by grouping test
imports after other cinderclient imports.

Change-Id: Ie40fda014d1aedb057e5b4ea1f27f999c84e6373

Now v2 API uses code from v3. It's confusing and logically incorrect.
This patch makes v3 API as an extended version of v2.

The next patches related to this bug duplicated code between v1 and v2,
v2 and v3 will be removed.

Change-Id: I90a2b713556e91db69270a03ef6b798e08f93f90
Partial-Bug: #1643584

Added request_ids attribute to resource object for all the
cgsnapshots, consistencygroups, qos_specs, quota_classes,
quotas and services APIs by updating following APIs:

cgsnapshots: delete, update
consistencygroups: delete, update, create
qos_specs: delete, associate, disassociate, disassociate_all
quota_classes: update
quotas: update
services: enable, disable, disable_log_reason

These changes are required to return 'request_id' from client to
log request_id mappings of cross projects.

For more details on how request_id will be returned to the caller,
please refer to the approved blueprint [1] discussed with the
cross-project team.
[1] http://specs.openstack.org/openstack/openstack-specs/specs/return-request-id.html

DocImpact
'request-ids' will be returned as an attribute with response object.
User can access it using 'res.request_ids' where 'res' is a
response object.

Change-Id: I7b399512fcec9ecd31938656deb60e325bb76ad4
Partial-Implements: blueprint return-request-id-to-caller

This is the first step of moving functional testing
into the project tree.  This change just moves
all of the unit tests to be under a dedicated tests/unit
directory.

Follow up patches will add the functional directory and
start moving tempest CLI tests there.

Change-Id: I9dc0b8f761676c1b3bbdeb03e2f44b35f75c693e