staging: lustre: obd: cleanup struct md_op_data and uses

staging: lustre: obd: cleanup struct md_op_data and uses

Make the following changes in or around struct md_op_data:

 * rename enum op_cli_flags to enum md_cli_flags.

 * Change to type of the op_flags member from __u32 to enum
   md_op_flags.

 * Remove the used but never set member op_npages.

 * Remove the set but never used member op_stripe_offset (an alias for
   op_ioepoch).

 * Remove the op_max_pages alias for op_valid and add a op_max_pages
   member.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-2675
Reviewed-on: http://review.whamcloud.com/11734
Reviewed-by: Bob Glossman <bob.glossman@intel.com>
Reviewed-by: James Simmons <uja.ornl@gmail.com>
Reviewed-by: Dmitry Eremin <dmitry.eremin@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
Signed-off-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>