qemu_test: Rebase force-uid0-on-9p.patch

This reverts commit 3a4e2376

.

The reverted commit caused the fix for CVE-2016-9602 not to be applied
for qemu_test because it conflicts with the force-uid0-on-9p.patch.

So with the rebase of the patch on top of the changes of the
CVE-2016-9602.patch, both patches no longer conflict with each other.

I've tested this with the "misc" NixOS test and it succeeds.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>