Fixes Hyper-V agent force_hyperv_utils_v1 flag issue

WMI root\virtualization namespace v1 (in Hyper-V) has been removed
from Windows Server / Hyper-V Server 2012 R2.

Hyper-V compute agent now creates instances which uses
root\virtualization\v2 namespace if the agent's OS is
Windows Server / Hyper-V Server 2012 R2 or newer.

Closes-Bug: #1344036
(cherry picked from 52de9395e5fe4f328f6dab0b35d660a700787c76)

Change-Id: I874ade4456b92a63959a765c7851bcd001befa32
Merge "Fixes Hyper-V agent force_hyperv_utils_v1 flag issue" into stable/icehouse