Fix updating device names when defaulting

If the virt driver does not support defaulting device names, the default
behaviour of defaulting them in the manager was calling the conductor
block_device_mapping_update method with the wrong arguments, which
caused a TypeError and ultimately a failure to boot the instance.

This patch fixed the signature and adds a test that exercises it so
that it does not regress.

Closes-bug: #1260806
Change-Id: I6116540c9aca4847afacf80b3d1e0c027c364159
VM diagnostics (v3 API only)

There is no formal definition for the VM diagnostics. For the
V2 API the diagnostics will be returned as they are today.

This will continue to use the driver function get_diagnostics.

For the V3 api the diagnostics will have the format defined at:
https://wiki.openstack.org/wiki/Nova_VM_Diagnostics

This change will be implemented by a new virt driver method called
get_instance_diagnostics.

This will support backward compatibility with the existing API's.

Part of the blueprint v3-diagnostics

This patch set is for the API's. Virt driver support in additional
patches.

DocImpact

Change-Id: Id722f38fb134b322413d2b5c3459c8fc0af7bd36
XenAPI: VM diagnostics for v3 API

For V3 API the diagnostics will have the format defined at:
https://wiki.openstack.org/wiki/Nova_VM_Diagnostics

This will support backward compatability with the existing APIs

Part of the blueprint v3-diagnostics

DocImpact

Change-Id: I8377f86a97ca554028e4ca8c1c1af7fd5643cc2e
Merge "Fix updating device names when defaulting"
Merge commit 'refs/changes/53/58753/9' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/54/58754/11' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/55/58755/10' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/61/58861/10' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/53/60253/7' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch

Conflicts:
	nova/virt/xenapi/vm_utils.py
Merge commit 'refs/changes/08/60808/6' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/78/63778/1' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/38/66338/4' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch
Merge commit 'refs/changes/97/66597/3' of git://gold.eng.hq.xensource.com/git/github/openstack/nova into tmpbranch