LU-9771 osp: no delay commit callback for layout version

LU-9771 osp: no delay commit callback for layout version

OSP batches commit callback by one second interval. However, this
mechanism would cause problem to FLR because the clients has to
wait up to one second before they are able to write OST objects.

This patch registers immediate commit callback if the SETATTR is
for layout version. It also cleans up the code a little bit.

Signed-off-by: Jinshan Xiong <jinshan.xiong@intel.com>
Change-Id: I5fa0fea9a8c8b23379118609bee9a36f412a191d
Reviewed-on: https://review.whamcloud.com/30000
Reviewed-by: Alex Zhuravlev <alexey.zhuravlev@intel.com>
Reviewed-by: Lai Siyao <lai.siyao@intel.com>
Tested-by: Jenkins
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>