LU-6401 uapi: split lustre_disk.h into two headers

LU-6401 uapi: split lustre_disk.h into two headers

The header lustre_disk.h is used by both user and
kernel space but it contains kernel specific material.
Split out the material that is used by both user land
and kernel space into a new header. Change the utilities
over to using this new UAPI header while the lustre
kernel code keeps using the kernel version of
lustre_disk.h.

Change-Id: I2cc75e4e465e17cc45bebb3b61e2e16d4bd615f0
Signed-off-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-on: https://review.whamcloud.com/25194
Tested-by: Jenkins
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: John L. Hammond <john.hammond@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>