Fix for poweroff issue (bug #994899)
I've build packages with these patches included and my Xen server shuts down properly with that.
We had already identified 3 commits which we later found to all belong to 1 patch-set, so I took the whole patch-set.
Also identified another commit which was a (further) fix to that patch-set, so I included that as well.
Also added a changelog entry to give it a unique version name so I could verify that I was actually running that version and to document where those patches came from. The CI failed because it wasn't happy with the version number. Feel free to not include that changelog commit, but I included it so that this MR does have all the relevant information (AFAIC).
It's also fine to not merge this MR but implement the fix a different way. In that case, see this MR as proof that these additional commit do fix bug #994899 for me.