fix missing flag for btrfs balance in disk-maintenance

install/usr/local/bin/disk-maintenance

@@ -13,7 +13,7 @@ done
 
 # rebalance and trim SSD btrfs (HDD are too slow and should be done manually)
 for filesystem in $(mount -t btrfs | grep "ssd" | awk '{print $3}'); do
-	btrfs balance start -musage=11 dusage=10 "$filesystem"
+	btrfs balance start -musage=11 -dusage=10 "$filesystem"
 	fstrim "$filesystem"
 done