Fixes instance task_state being left as migrating

In a cross-hypervisor environment, such as KVM + Hyper-v. After negative test
which live migrate a KVM instance to Hyper-v host, there will be an exception
InvalidHypervisorType. As a result, the instance task_state is being
left as migrating. That leaves the instance in a broken state and most of the
requests on the instance will fail.

Actually, there are some other exceptions will cause this issue as well, such
as UnableToMigrateToSelf, DestinationHypervisorTooOld. All of them are thrown
from the driver of scheduler during live migration. But obviously, if the live
migration fails at the schedule stage, the task_state of the target instance
should be updated to None.

Fixes Bug: 1153283

Change-Id: Ide4b48653268c8dbe31de6964814830d2e82a5ba
Fixes Hyper-V live migration with attached volumes

Fixes bug: 1153429

The previous Hyper-V driver live migration implementation expects to find iSCSI
devices mounted on the same path on source and destination, which is not an
option in this context.

In order to be able to live migrate instances with attached volumes, this fix
provides the following behavior, based on the creation of a staged VM on the
target, so called "planned" in the Hyper-V documentation and in this patch.

pre_live_migration

The target host logs into the storage targets.

live_migration

The source host:

1) checks and removes a previously created planned VM for the current
   instance if present on the target
2) creates a planned VM on the target by using the Hyper-V WMI API
3) maps the volume devices on the planned VM based on the target host
   devices
4) live migrates the source VM on the planned VM
5) logs off the storage targets on the source

This solution provides live migration of volumes without needing to pause
the VM and detach / attach the volumes, preserving also the atomicity of the
live operation.

In the case in which no volumes are attached to the VM, live migration is
performed without creating explicitly a planned VM, starting from step 4
on the source in the above list.

Unit tests have been added for this scenario.

Change-Id: Ib634b77894f492896d86dce65a7269ece8f3d55b
Add missing API doc for networks-post-req.

Part of the os-tenant-networks API extension.

Fixes LP Bug #1155303.

Change-Id: Ic71a3d108f9401ec81d2c59a6f7ba3ec6ab59dd8
Fix exception message in Networks API extension

Raise exception indicating VLAN is disabled when
trying to associate a network w/ a tenant in cases where
VLAN is not the network manager
Added unit test case
Fixes bug 1075790

Change-Id: I3dcac09fbf06d9f64b18cc52d0b069dc9c0a7370
Imported Translations from Transifex

Change-Id: I9e57c57edc56e0bf68797ccfc920a119bb57905f
Merge "Fixes Hyper-V live migration with attached volumes"
Merge "Imported Translations from Transifex"
Merge "Fix exception message in Networks API extension"
Merge "Add missing API doc for networks-post-req."
Merge "Fixes instance task_state being left as migrating"