Don't update DB records for unchanged stats.

Change-Id: I6eb0adba12676cf057c92fb0b54431cfe6a76210
Remove tempest hack for create/rebuild checks

A bug in Tempest required us to check quotas before requesting image
information. Now that this has been fixed upstream, we can remove our hack to
get around this.

Change-Id: I7ef1cd2f4f641fb5616945b66740820a4003b66d
Raise exception instances not exception classes

Replaces deprecated syntax of raising an exception class
with raising an instance of the exception class instead

Change-Id: Icb127c6a93de7faab5db8d1f037095bbbb82a229
compute.api call conductor ComputeTaskManager for live-migrate

Before the compute api called the scheduler to perform
live migrate. This change makes the compute api call the
conductor, which in turn calls the scheduler.

For those not using the conductor service,
this does not add any extra rpc calls.

This change in control flow means we can look to move
live-migrate more related rpc calls into the conductor
from both schduler driver and compute manager.

part of blueprint live-migration-to-conductor
Change-Id: I081c5e090921d69878d044839616a48f198ecb7d
Make pylint ignore nova/objects/

The dynamic nature of our object model is going to cause lots of
heartache for pylint, especially in the actual definitions. This
just excludes that whole directory from pylint's view, which will
limit the heartache to only everywhere objects are actually used.

Related to blueprint unified-object-model

Change-Id: I7f1a4b10b8a5098aab2ab2e8ea5da15ec43f0e2e
Merge "compute.api call conductor ComputeTaskManager for live-migrate"
Merge "Don't update DB records for unchanged stats."
Merge "Make pylint ignore nova/objects/"
Merge "Raise exception instances not exception classes"
Merge "Remove tempest hack for create/rebuild checks"