Revert "Fix disk utilization for md/dm slaves"

This reverts commit f03f8e473b7c8a5c4ed2de0b99717cf75521bf69.
diff --git a/diskutil.c b/diskutil.c
index ac2f006..e90096b 100644
--- a/diskutil.c
+++ b/diskutil.c
@@ -236,10 +236,8 @@
 
 		/* Should probably use an assert here. slavedu should
 		 * always be present at this point. */
-		if (slavedu) {
-			slavedu->users++;
+		if (slavedu)
 			flist_add_tail(&slavedu->slavelist, &masterdu->slaves);
-		}
 	}
 
 	closedir(dirhandle);
@@ -545,7 +543,6 @@
 	flist_for_each_safe(entry, next, &disk_list) {
 		flist_del(entry);
 		du = flist_entry(entry, struct disk_util, list);
-		du->users--;
 		disk_util_free(du);
 	}
 }