Update to 4.9.2~pre+1.32e364c4e7

Update to 4.9.2~pre+1.32e364c4e7

So, to reiterate... the orig tar will just be made from commit
32e364c4e7 in the upstream repo. And if we advance to a later point
before 4.9.3 is released, then it'll get 4.9.2~pre+2.<commitid> etc...

Update the packaging for Xen 4.9. I took these changes from the Xen 4.9
packaging in Ubuntu done by Stefan Bader. Thanks!