Minor lbaasv2 things from the feature branch, needed in neutron

- Minor neutron.conf fix from feature branch until config is moved
- Some extra constants for extension
- Jinja template entry in services.conf

Change-Id: I4a15d0ac422457d2286d4b24d9f5067047e81563
Partially-Implements: blueprint services-split
Co-Authored-By: Brandon Logan <brandon.logan@rackspace.com>
Scope dhcp rpc api using a messaging namespace

This patch updates the rpc API used by the DHCP agent to make calls
back into the neutron plugin to use the 'dhcp' namespace instead of
the default namespace.  The reason is that this API is exposed over
the 'q-plugin' topic along with several other interfaces.  Without the
use of namespaces, all of the interfaces are effectively treated as
one by oslo.messaging.  When a namespace is used, the interface can be
versioned independently and when a method is called, the only class
considered for fulfilling the request is the one that claims to
implement the 'dhcp' namespace.

While we're here, add documentation to both the client and server side
of this interface that indicates where the other side is located.

Part of blueprint rpc-docs-and-namespaces.

Change-Id: I9e56aa34fc560ae3fc749c51788436e32179d0a1
Copy the contrib directory instead of moving it

This is necessary because pbr is stupid enough not to be
able to handle symlinks. The initial symlink was necessary to
avoid breaking the functional job. Once change [1] merges we
can drop the old contrib directory.

[1] https://review.openstack.org/#/c/142603/

Change-Id: I683009b1c5b3520e5f9f2c17a9a0dabefdeebe45
Merge "Scope dhcp rpc api using a messaging namespace"
Merge "Minor lbaasv2 things from the feature branch, needed in neutron"