[FIXED] [Mage][Arcane] Arcane Barrage vs AM proc

[Pinocchio Evreiesc]

WoW Freakz spell link: Arcane Barrage
Bug description: The dice roll for a chance to proc arcane missiles should be done on CAST. Currently it is done when the spell reaches the target which can lead to proc munching at certain distances or versus large bosses where barrage has a very long travel time.
Proof:How it should work (retail), can be clearly seen at 5:15
https://youtube.com/watch?v=ST9qYaNRI6U:

[Quicksand]

Fixed