Some fixes for bugreport:8633 http://rathena.org/board/tracker/issue-8633-about-this-commit-skills/
- Added some dummy Skill IDs tp skill_copyable_db.txt
- Demonic fire doens't have duration for lv 2 and 5
- Typo on skill_require_db.txt for Siena Execrate

Signed-off-by: Cydh Ramdh <house.bad@gmail.com>