Hyper-V Fixes for Hydrogen

The following pull request resolves the following issues with VyOS under a Hyper-V Host:

* During installation of VyOS to system, the system detects there are 2 VHD's attached to the IDE bus when in fact there is only one VHD attached to the bus. By backporting fixes from later upstream kernel branches that ignores the duplicate VHD, this patch resolves the issue.
* NetVSC - Disconnecting and Reconnecting the NIC shouldn't cause any kernel warnings anymore.

IIRC, VLAN Trunking functionality is still broken in the 3.8 branch. I may backport those fixes if there is a significant demand for it.