Ensure that agents also set control_exchange

Fixes bug 1100357

Change-Id: I6302edecf851588762d39c99d2f7b2e18ba04bc7
Merge "Ensure that agents also set control_exchange"
_validate_security_groups_on_port was not validating external_ids

The function _validate_security_groups_on_port was not validating a ports
security group id if the id was an external id. The unit tests now use
set_override() rather than setting cfg values directly. Lastly, quantum.conf
now has the proxy_mode option exposed.
Fixes bug 1095864

Change-Id: I0ec7f9ed36f1a46156c47a115be936bb41ef75d9
Refactor hyperv plugin and agent.

Remove unused imports.
Add an empty tunnel_sync method so that we can run ovs-quantum-agent
with the hyper-v plugin when we are using vlan networks.

Change-Id: I94b1d0cf188d0a1e03e0948708975594f2615fbf
Fixes inefficiency in quantum.api.v2.base._filters

Use iteritems() instead of getall() on request.GET

Fixes bug #1092995

Change-Id: Ic0b5e3d7c7b1ddd072d9fe918ea22a8e9aef9ee4
Merge "Refactor hyperv plugin and agent."
Merge "_validate_security_groups_on_port was not validating external_ids"