[SCSI] osd: Remove out-of-tree left overs

* Delete Makefile. It is only used for out-of-tree compilation
  and was never needed. It slipped in by mistake.
* Remove from Kbuild all the out of tree stuff as promised.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>