s390/dasd: fix memory leak caused by dangling references to request_queue

After the call to del_gendisk, the gendisk still holds a reference to
its request_queue. We must not modify the gendisks queue pointer
before the put_disk call, or the gendisk_release function cannot
release the reference and the memory for the request_queue structure
is lost.
Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

drivers/s390/block/dasd_genhd.c

@@ -87,7 +87,6 @@ void dasd_gendisk_free(struct dasd_block *block)
 {
 	if (block->gdp) {
 		del_gendisk(block->gdp);
-		block->gdp->queue = NULL;
 		block->gdp->private_data = NULL;
 		put_disk(block->gdp);
 		block->gdp = NULL;