LU-11418 osd-zfs: call stop_cb if transaction start fail

LU-11418 osd-zfs: call stop_cb if transaction start fail

osd_trans_stop() should call osd_trans_stop_cb() if transaction is
not successfully started.

Improve debug messages for distribute transaction.

Add sanity 416 for this.

Get rid of ot_write_commit which is useless.

Signed-off-by: Lai Siyao <lai.siyao@whamcloud.com>
Change-Id: I35da81ebd2c9e97c12ae52bd4faed60393cd67d6
Reviewed-on: https://review.whamcloud.com/33248
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Jenkins
Reviewed-by: Alex Zhuravlev <bzzz@whamcloud.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>