LU-2675 obd: remove linux/obd.h

LU-2675 obd: remove linux/obd.h

Remove the now unneeded header lustre/include/linux/obd.h.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I70c0b40fded991b1e871bf8624cb91f39e065ea7
Reviewed-on: http://review.whamcloud.com/13123
Tested-by: Jenkins
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>