Deprecate neutron_* configuration settings

Create a new section in the configuration file called 'neutron'.
Move all of the neutron_* configuration settings to this section.

DocImpact

The table below has the changes:

+---------------------------------+-------------------------+
| 'DEFAULT' Section               | 'neutron' Section       |
|---------------------------------|-------------------------|
| neutron_url                     | url                     |
| neutron_url_timeout             | url_timeout             |
| neutron_admin_username          | admin_username          |
| neutron_admin_password          | admin_password          |
| neutron_admin_tenant_id         | admin_tenant_id         |
| neutron_admin_tenant_name       | admin_tenant_name       |
| neutron_region_name             | region_name             |
| neutron_admin_auth_url          | admin_auth_url          |
| neutron_api_insecure            | api_insecure            |
| neutron_auth_strategy           | auth_strategy           |
| neutron_region_name             | region_name             |
| neutron_ovs_bridge              | ovs_bridge              |
| neutron_extension_sync_interval | extension_sync_interval |
| neutron_ca_certificates_file    | ca_certificates_file    |
+---------------------------------+-----------------------=-+

UpgradeImpact
The changes are backward compatible.

Change-Id: I3308be33f60c4add3e2e78b75f238059a9b3d876
Add configurable HTTP timeout to cinder API calls

Some Nova API calls require synchronous use of cinder.  (e.g. volume
list)  If the call to cinder lands on a slow performing or otherwise bad
cinder API node, the user of Nova API will see poor performance.

This patch adds the ability to control HTTP timeouts when calling the
cinder API.  By configuring a timeout, nova will be able to more quickly
retry its cinder request and hopefully land on a better performing
cinder API node.  This will help make the API response times more
predictable.

For backward compatibility, the default timeout value is None.

Closes-Bug: 1329797
DocImpact

Change-Id: I5cccced524d9a9d69ed41f755781d0b7ae3dc970
Add test for HypervisorUnavailable on conductor

HypervisorUnavailable is added in excepted exception list in conductor
function migrate_server in commit d0a5e272, but the test cases are not added.
This patch adds test cases for it.

Change-Id: I83556e97cb151ff202b2377c00122a368b1c2892
Merge "Deprecate neutron_* configuration settings"
Merge "Add test for HypervisorUnavailable on conductor"
Merge "Add configurable HTTP timeout to cinder API calls"