drivers/md/persistent-data/dm-transaction-manager.c: rename HASH_SIZE

drivers/md/persistent-data/dm-transaction-manager.c: rename HASH_SIZE

drivers/md/persistent-data/dm-transaction-manager.c:28:1: warning: "HASH_SIZE" redefined
In file included from include/linux/elevator.h:5,
                 from include/linux/blkdev.h:216,
                 from drivers/md/persistent-data/dm-block-manager.h:11,
                 from drivers/md/persistent-data/dm-transaction-manager.h:10,
                 from drivers/md/persistent-data/dm-transaction-manager.c:6:
include/linux/hashtable.h:22:1: warning: this is the location of the previous definition
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>