[SCSI] fix propogation of integrity errors

When the Integrity check is done in scsi_io_completion it will
set error to -EILSEQ. However, at this point error is no longer
used, and blk_end_request_err has -EIO hardcoded.

It looks like there was just porting mistake with this patch
http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=3e695f89c5debb735e4ff051e9e58d8fb4e95110
and we meant to send error upwards, so this patch changes the hard
coded EIO to the error variable.

I have only boot tested this patch.

Signed-off-by: Mike Christie <michaelc@cs.wisc.edu>
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>