[PATCH] SCSI: Introduce scsi_req_abort_cmd (REPOST)

Introduce scsi_req_abort_cmd(struct scsi_cmnd *).
This function requests that SCSI Core start recovery for the
command by deleting the timer and adding the command to the eh
queue.  It can be called by either LLDDs or SCSI Core.  LLDDs who
implement their own error recovery MAY ignore the timeout event if
they generated scsi_req_abort_cmd.

First post:
http://marc.theaimsgroup.com/?l=linux-scsi&m=113833937421677&w=2

Signed-off-by: Luben Tuikov <ltuikov@yahoo.com>
Signed-off-by: Tejun Heo <htejun@gmail.com>