[xen/f15] (5 commits) ...improve systemd functionality (second attempt)

[myoung]

Summary of changes:

  df2a330... partial migration to systemd to fix shutdown delays (*)
  4b8e3c5... update grub2 configuration after hypervisor updates (*)
  ce2f151... fix typo in spec file (*)
  0d77316... improve systemd functionality (*)
  bc53f7c... improve systemd functionality (second attempt) (*)

(*) This commit already existed in another branch; no separate mail sent