Remove instance_uuids from request_spec

instance_uuids was previously deprecated in Scheduler RPC API 3.0, so now we
bumped the version to 4.0, there is no longer methods which need this.

So, we can just remove it from FilterScheduler._schedule() method and also
leave sched_utils.set_vm_state_and_notify() method use the uuid from
instance_properties.
scheduler_utils.setup_instance_group() is also modified to get the uuid
from instance_properties.

Change-Id: I26003dc27a2bc3f30f1b09000533b571096c8b21
Partially-Implements: blueprint request-spec-object
Merge "Remove instance_uuids from request_spec"