scsi: remove dead code from sr.c

This patch fixes an issue reported in drivers/scsi/sr.c by Coverity

Error reported: Pointer returned from "scsi_cd" is never used

Patch description:
Remove the scsi_cd() call as it does not have any effect.

---

 sr.c |    2 +-
 1 files changed, 1 insertion(+), 1 deletion(-)

@@ -455,7 +455,7 @@
 static int sr_block_open(struct inode *inode, struct file *file)
 {
 	struct gendisk *disk = inode->i_bdev->bd_disk;
-	struct scsi_cd *cd = scsi_cd(inode->i_bdev->bd_disk);
+	struct scsi_cd *cd;
 	int ret = 0;
 
 	if(!(cd = scsi_cd_get(disk)))