WZ_WATERBALL attack range fix

Since WZ_WATERBALL can be obtained until lv 10 by Plagiarism, it needs defined range until lv 10, or it will makes the range will be 1 and player never get 9 range when targetting the skill.

bugreport http://rathena.org/board/tracker/issue-8402-waterball-above-level-5-with-wrong-attack-range/

Signed-off-by: Cydh Ramdh <house.bad@gmail.com>