LU-1235 osd: debug patch for transaction commit callback

LU-1235 osd: debug patch for transaction commit callback

During transaction commit phase, osd_trans_commit_cb accesses an
invalid memeroy, this patch insert some assertions to find out the
possible faulty point.

Signed-off-by: Bobi Jam <bobijam@whamcloud.com>
Change-Id: Idb39a6946fbd5d8a96ee6915f828f557ccebadb6
Reviewed-on: http://review.whamcloud.com/2394
Tested-by: Hudson
Reviewed-by: Mike Pershin <tappro@whamcloud.com>
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Liang Zhen <liang@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>