Adds Hyper-V serial console log

Introduces the VM serial output log feature to the Hyper-V Nova
Compute driver.

The VM serial port COM0 is redirected to a named pipe so that a
worker can take the VM output and write it to a file.

The VM serial output is then read from this file whenever the
console log command is issued.

Implements: blueprint hyper-v-console-log

Co-Authored-By: Adelina Tuvenie <atuvenie@cloudbasesolutions.com>

Change-Id: I7d3132c0f934ac3e8d28315f4da766466612a6c0

Conflicts:
	nova/tests/virt/hyperv/test_hypervapi.py
	nova/tests/virt/hyperv/test_vmutils.py
	nova/virt/hyperv/vmops.py
Merge branch '2014.1.2-cloudbase-release' of https://github.com/cloudbase/nova into 2014.1.2-cloudbase-release
Fixes Hyper-V boot from volume root device issue

Checks that instances are booting from volume by checking
the correct root device obtained from the block device info.

Change-Id: I94941dfe96c1596c8e9b91df3d3d19d33ae7fe92
Co-Authored-By: Zsolt Dudas <zdudas@cloudbasesolutions.com>
Closes-Bug: #1357972
Adds get_instance_disk_info to compute drivers

Solves a live migration regression issue by adding the
get_instance_disk_info to the compute drivers that do not
have it already implemented.

The method is called by the compute manager.

Change-Id: If5cd9a6f5948c08ef5f1cba2eda31f1175709137
Closes-Bug: #1358719
Co-Authored-By: Ionut Balutoiu <ibalutoiu@cloudbasesolutions.com>