LU-11014 mdt: intent handling simplification

LU-11014 mdt: intent handling simplification

Remove the obsolete constants MDT_IT_CREATE, MDT_IT_READDIR,
MDT_IT_UNLINK, and MDT_IT_TRUNC from enum mdt_it_code. Also remove
MDT_IT_OCREAT, since (at this level) it can be handled identically to
MDT_IT_OPEN. Rename mdt_intent_reint() to mdt_intent_open() since it
only handles open. Move the definition of the mdt_it_flavor array down
and remove the then unneeded forward declarations of mdt_intent_*().
In struct mdt_it_flavor, remove the obsolete it_reint member and
rename the it_flags member to it_handler_flags to avoid confusion with
LDLM flags. Use 'enum tgt_handler_flags' rather than __u32 for several
parameters used to hold values of that type.

Signed-off-by: John L. Hammond <john.hammond@intel.com>
Change-Id: I297ef397c879fcc7711d725e0315e73439d95826
Reviewed-on: https://review.whamcloud.com/32357
Reviewed-by: Mike Pershin <mike.pershin@intel.com>
Tested-by: Jenkins
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Fan Yong <fan.yong@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>