Fixes get_vm_storage_paths issue for Hyper-V V2 API

Add get_vm_storage_paths function to vmutilsv2.py

get_vm_storage_paths implementation on Hyper-V V2 API changed
compared to previous V1 API. In previous V1 APIs, using
Msvm_ResourceAllocationSettingData class can get storage
paths, but in V2 API, only using Msvm_StorageAllocationSettingData
class can get the storage paths.

Closes-Bug: #1248463

Change-Id: Ica73221524f162a6ffcd9dc64ee33c85fb5ad31d
(cherry picked from commit 6847a0ef927929e631e9c6db2e2812528ca93151)
Fixes Hyper-V issue with VHD file format

The VHD format cookie signature needs to be checked in the footer
instead of the header as fixed format VHDs don't have a copy of the
footer at the beginning of the file.

Fixes bug: #1233853

(cherry-picked from commit fdc5a57d03b9a53981dc0e1623091980570456eb)

Conflicts:

	nova/tests/virt/hyperv/test_vhdutils.py

Change-Id: Ibe44f0d895cde2edbc03dcd6ecebac24b0936660
Merge "Fixes get_vm_storage_paths issue for Hyper-V V2 API" into stable/havana
Merge "Fixes Hyper-V issue with VHD file format" into stable/havana