Add nova::scheduler::filter to nova_controller

The current nova_controller classgroup doesn't include
the nova::scheduler::filter class, which leaves end
users without the ability to modify scheduler filters.
This patch adds it.

Change-Id: I689919048a22eac1fdcae918dde1509fbed5863f
Closes-Bug: #1354458
(cherry picked from commit b2fd7baafad5c0fe7d136066b87446753916d31e)
Merge "Add nova::scheduler::filter to nova_controller" into stable/icehouse