filter_scheduler: Remove schedule() method
filter_scheduler: Remove schedule() method

This is never actually called, only _schedule()
or schedule_create_volume() are used.

It also doesn't appear to work since it passes
the topic as the second parameter to _schedule(),
which should be a request_spec.

Change-Id: I6befa027626dc468eeda8a8f10af0be10caf661a

openstack/cinder,mahak/cinder,openstack/cinder,mahak/cinder