6326 Eliminate unused filesystems from GRUB's stage 2 to bring back free memory

*** 28,37 ****
  # The version field contains the version of the associated GRUB software.  The
  # version is incremented by 1 each time there is a bugfix or enhancement to
  # GRUB necessitating that the boot blocks be reinstalled for that fix or
  # enhancement to take effect.
  #
! VERSION=26
  dboot
  xVM
  zfs
  findroot
--- 28,37 ----
  # The version field contains the version of the associated GRUB software.  The
  # version is incremented by 1 each time there is a bugfix or enhancement to
  # GRUB necessitating that the boot blocks be reinstalled for that fix or
  # enhancement to take effect.
  #
! VERSION=27
  dboot
  xVM
  zfs
  findroot