Attach/detach interface to paused instance with affect live flag

Currently attach/detach interface to paused instance is only with
VIR_DOMAIN_AFFECT_CONFIG flags. After instance unpause, there isn't
any effect on the instance, unless restart the instance. So add
flag VIR_DOMAIN_AFFECT_LIVE when attach/detach interface.

Conflicts:
	nova/tests/virt/libvirt/test_libvirt.py

Change-Id: Iedfc7f6fc06e72d8e3eecebede1274582c8043fd
Closes-Bug: #1299331
(cherry picked from commit a868fcedf8e46070cae6aa8e59e61934fa23db1c)
Do not process events for instances without host

In some cases Neutron might send events such as 'VIF unplugged'
for instances which are either being deleted or shelved. When
that happens there will be a failure in dispatching the event
to the appropriate compute node - as there is no host for the
instance.

As multiple neutron events can be stashed in a single call
it is important to avoid that this kind of errors will prevent
processing of other events in the same call.

This patch does not process events for instances without a host,
marking them as failed.

When the above condition occurs, the create event request will
return a 207 response code. For specific events, a 422
unprocessable entity code will be set.

This patch also preserve the characteristic that events are
returned in the response in the same order they were found in
the request.

Change-Id: I18062b81e50c722ec96b4296ac39384493683ae3
Closes-Bug: #1333654
(cherry picked from commit 4f8ccd7b95c27180a1cfe689e3c6f46bde5f803b)
Do not pass instances without host to compute API

Even if the server external events extension filters out events
whose related instance does not have a host, the corresponding
instance is still sent to the compute API module.
As this might result in KeyError, instance without host should
be filtered out before calling the compute API module.

Change-Id: If5229ec3059076dbc9f4abb6625504e8864c265e
Closes-Bug: #1348584
(cherry picked from commit 5e4a5f0d8c62ca6e94ae6db16e9fbe0428805158)
Merge "Do not process events for instances without host" into stable/icehouse
Merge "Do not pass instances without host to compute API" into stable/icehouse
Merge "Attach/detach interface to paused instance with affect live flag" into stable/icehouse