Functional tests for NUMA live migration

This patch add a functional tests for NUMA live migration. It also
adds all the previously missing scaffolding, specifically:

* Make the fakelibvirt Domain support the vcpupin, memnode and
  emulatorpin XML elements.

* To support testing RPC pinning, a new StubComputeRPCAPI is added to
  the integrated helpers. It replaces the real ComputeAPI's router()
  method with a stub that uses the RPC version set by the object's
  __init__. Tests can replace a real ComputeAPI object with the Stub
  to simulate compute services and/or conductors being pinned to
  different RPC versions.

* In the fake_imagebackend, is_shared_block_storage() gets stubbed.
  It's called indirectly from the
  _check_can_live_migrate_(source|destination) checks.

Implements blueprint numa-aware-live-migration
Change-Id: Ia3d7351c1805d98bcb799ab0375673c7f1cb8848

Author: notartom

nova/tests/functional/integrated_helpers.py

@@ -24,15 +24,20 @@
 import time
 
 import os_traits
+from oslo_concurrency import lockutils
 from oslo_log import log as logging
+import oslo_messaging as messaging
 
 from nova.compute import instance_actions
+from nova.compute import rpcapi as compute_rpcapi
 from nova.compute import utils as compute_utils
 import nova.conf
 from nova import context
 from nova.db import api as db
 import nova.image.glance
 from nova import objects
+from nova.objects import base as objects_base
+from nova import rpc
 from nova import test
 from nova.tests import fixtures as nova_fixtures
 from nova.tests.functional.api import client as api_client
@@ -72,6 +77,26 @@ def generate_new_element(items, prefix, numeric=False):
         LOG.debug("Random collision on %s", candidate)
 
 
+class StubComputeRPCAPI(compute_rpcapi.ComputeAPI):
+    """Stub ComputeAPI that allows us to pin the RPC version of a host. Used to
+    simulate rolling upgrade situations where either source, dest or conductor
+    are pinned.
+    """
+
+    def __init__(self, version):
+        self.version = version
+
+    @property
+    def router(self):
+        with lockutils.lock('compute-rpcapi-router'):
+            target = messaging.Target(topic='compute', version='5.0')
+            version_cap = self.version
+            serializer = objects_base.NovaObjectSerializer()
+            rpc.get_client(target, version_cap, serializer)
+            default_client = self.get_client(target, version_cap, serializer)
+            return rpc.ClientRouter(default_client)
+
+
 class InstanceHelperMixin(object):
 
     def _wait_for_server_parameter(