[2876] Fix bug in Hyjal instance script

Thanks Azelen for pointing

Close #58
[2877] Update some scripts after CMangos [12322]

Conflicts:
	scripts/eastern_kingdoms/sunwell_plateau/boss_brutallus.cpp
	scripts/northrend/gundrak/instance_gundrak.cpp
	scripts/northrend/violet_hold/instance_violet_hold.cpp