Scripts/Spells: Corrections to Ring of Frost:

* Make players who got the debuff dispeled immune to the Ring of Frost effect for 3 secs.
* Corrected the way for selecting the last summoned RoF.
* Corrected radius.
* Change a little the general behaviour of coalesce system, so it doesn't interfere with the immunity part
* Added SQL.
Spells: Change Ring of Frost model for hostile players