Implements resize / cold migration on Hyper-V

Blueprint: hyper-v-compute-resize

Resize / cold migration is implemented by copying the local disks to a remote
SMB share, identified by the configuration option HYPERV.instances_path_share
or, if empty, by an administrative share with a remote path corresponding to
the configuration option instances_path.

The source instance directory is renamed by adding a suffix "_revert" and
preserved until the migration is confirmed or reverted. In the former case
the directory will be deleted and in the latter renamed to the original name.

The VM corresponding to the instance is deleted on the source host and
recreated on the target. Any mapped volume is disconnected on the source
and reattached to the new VM on the target host.

In case of resize operations, the local VHD file is resized according to
the new flavor limits. Due to VHD limitations, an attempt to resize a disk
to a smaller size will result in an exception.

In case of differencing disks (CoW), should the base disk be missing
in the target host's cache, it will be downloaded and reconnected to the
copied differencing disk.

Same host migrations are supported by using a temporary directory
with suffix "_tmp" during disk file copy.

Unit tests have been added for the new features accordingly.

Change-Id: Ieee2afff8061d2ab73a2252b7d2499178d0515fd
Adding support for AoE block storage SANs.

Adding support for AoE (ATA over Ethernet) block storage SANs.
AoE initiator driver is supported on all Linux initiators
(released under GPL), ATA over Ethernet (AoE) Linux driver
for all 3.x and 2.6 kernels.

Implements blueprint libvirt-aoe

   - Fix (minor) Redundant exception caching

Change-Id: I00de13eb2d4bd1105b9eb68f1465825414e2d5d7
Merge "Implements resize / cold migration on Hyper-V"
Merge "Adding support for AoE block storage SANs."