[SCSI] libosd: fix blk_put_request called from within request_end_io

[SCSI] libosd: fix blk_put_request called from within request_end_io

A fix for a very serious and stupid bug in osd_initiator. It
used to call blk_put_request() regardless of if it was from
the end_io callback or if called after a sync execution.
It should call the unlocked version __blk_put_request() instead.

Also fixed is the remove of _abort_unexecuted_bios hack, and use of
blk_end_request(,-ERROR,) to deallocate half baked requests. I've
audited the code and it should be safe.

Reported and
Tested-by: Xu Yang <onlyxuyang@qq.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>