Patch for MS Hyper V (virtualization)

[Ivan Voras]

Can someone please review and commit (if appropriate) the tweak for
Hyper-V shutdown issue at http://shell.peach.ne.jp/aoyama/archives/40
?

The problem is: the VM appears to hang on shutdown without it (hanging
the Hyper-V VM with it so the host also can't shutdown or reboot
reliably - someone at MS skipped the part where an error in the VM
isn't supposed to bring the host down with it)