[SCSI] fix recovered error handling

We have a problem with recovered error handling in that any command
which goes down as BLOCK_PC but which returns a sense code of RECOVERED
ERROR gets completed with -EIO.  For actual SG_IO commands, this doesn't
matter at all, since the error return code gets dropped in favour of
req->errors which contain the SCSI completion code.

However, if this command is part of the block system, then it will pay
attention to the returned error code.  In particularly if a SYNCHRONIZE
CACHE from a barrier command completes with RECOVERED ERROR, the
resulting -EIO on the barrier causes block to error the request and
return it to the filesystem.  Fix this by converting the -EIO for
recovered error to zero, plus remove the printing of this from sd and sr
so the message isn't double printed.

Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sr.c

@@ -309,15 +309,6 @@ static int sr_done(struct scsi_cmnd *SCpnt)
 			break;
 
 		case RECOVERED_ERROR:
-
-			/*
-			 * An error occured, but it recovered.  Inform the
-			 * user, but make sure that it's not treated as a
-			 * hard error.
-			 */
-			scsi_print_sense("sr", SCpnt);
-			SCpnt->result = 0;
-			SCpnt->sense_buffer[0] = 0x0;
 			good_bytes = this_count;
 			break;