Sync oslo rpc

Sync openstack/common/rpc to fbbb12ea5ff51df744d3de1f312bbcf75aea1670
so we get the fixes required for bug 1257293

Change-Id: Ib2f13d1af91e005c5ee74d462c3fb307f699e7ca
Closes-Bug: #1257293
Refactor Instance#_check_active

Currently, Instance#_check_active both checks whether the server is
active and attaches the volume.  This commit separates that logic.

blueprint stack-check
Change-Id: I7fe805efc089535667e8d3840d79ade07430040c
Add way to group exceptions in DependencyTaskGroup

DependencyTaskGroup currently aborts execution if any exceptions are
raised.  This commit provides a way of aggregating all the exceptions
during execution and re-raising them only at the end.

blueprint stack-check

Change-Id: I6af314cc112f9286c8b38739870c6fa8b4ba9b5a
Sync resource statuses with real world resources

Attempt #2 - The Mission

This is just a work in progress to get feedback on how to go about doing
this.  This is the first step towards the auto heal/convergence
blueprint (stack-convergence).

The idea is to issue an update call with an additional flag to sync all
the resource statuses.

Once we figure out the correct way to go, this review will probably be
broken into smaller reviews.

No tests yet, just spiking.

Blueprint: stack-check
Change-Id: I4e39bfe6a3dca04305563844d5922da7e0bb67b3