testing/libguestfs: upgrade to 1.44.1
This upgrade is required for compilation with OCaml 4.12 that is now included in edge.
The python 3.8 patch has been reverted as it doesn't apply and the build appears to succeed without it - we're also on python 3.9.
I've included a new patch that ensures that everything compiles correctly even if --disable-ocaml is selected, I'll try and get this accepted upstream soon.
I've also expanded the arch support to everything except mips64 and s390x. This required removing the runtime dependency on qemu-system-* which should not be required as far as I know.
Additionally removed an unused variable and removed $pkgname from the download string to satisfy the linter.