xen to fix various denial of service issues (important)

This update of XEN fixes various denial of service bugs.

• bnc#789945 - CVE-2012-5510: xen: Grant table version
  switch list corruption vulnerability (XSA-26)

• bnc#789944 - CVE-2012-5511: xen: Several HVM operations
  do not validate the range of their inputs (XSA-27)

• bnc#789940 - CVE-2012-5512: xen: HVMOP_get_mem_access
  crash / HVMOP_set_mem_access information leak (XSA-28)

• bnc#789951 - CVE-2012-5513: xen: XENMEM_exchange may
  overwrite hypervisor memory (XSA-29)

• bnc#789948 - CVE-2012-5514: xen: Missing unlock in
  guest_physmap_mark_populate_on_demand() (XSA-30)

• bnc#789950 - CVE-2012-5515: xen: Several memory hypercall
  operations allow invalid extent order values (XSA-31)

• bnc#789988 - FATAL PAGE FAULT in hypervisor
  (arch_do_domctl)
  25931-x86-domctl-iomem-mapping-checks.patch

• Upstream patches from Jan
  26132-tmem-save-NULL-check.patch
  26134-x86-shadow-invlpg-check.patch
  26148-vcpu-timer-overflow.patch (Replaces
  CVE-2012-4535-xsa20.patch)
  26149-x86-p2m-physmap-error-path.patch (Replaces
  CVE-2012-4537-xsa22.patch)
  26150-x86-shadow-unhook-toplevel-check.patch (Replaces
  CVE-2012-4538-xsa23.patch)
  26151-gnttab-compat-get-status-frames.patch (Replaces
  CVE-2012-4539-xsa24.patch)

• bnc#777628 - guest "disappears" after live migration
  Updated block-dmmd script

• Fix exception in balloon.py and osdep.py
  xen-max-free-mem.diff

• bnc#792476 - efi files missing in latest XEN update
  Revert c/s 25751 EFI Makefile changes in
  23614-x86_64-EFI-boot.patch