drbd: reduce sizeof struct drbd_epoch_entry by 8 byte by aligning members

	struct hlist_node colision;

	struct hlist_node colision;

	sector_t sector;

	sector_t sector;

	unsigned int size;

	unsigned int size;

	struct drbd_epoch *epoch;

	/* up to here, the struct layout is identical to drbd_request;

	 * we might be able to use that to our advantage...  */

	unsigned int flags;

	unsigned int flags;

	struct drbd_epoch *epoch;

	u64    block_id;

	u64    block_id;

};

};