staging/lustre: remove empty file lustre/ptlrpc/nrs_orr.c

It is used by server only and we had it emptied with coan.

Signed-off-by: Peng Tao <tao.peng@emc.com>
Signed-off-by: Andreas Dilger <andreas.dilger@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>