Fix crash caused by FlameLeviathanPursuedTargetSelector

src/server/scripts/Northrend/Ulduar/ulduar/boss_flame_leviathan.cpp

@@ -1680,6 +1680,7 @@ class spell_pursue : public SpellScriptLoader
             void FilterTargetsSubsequently(std::list<Unit*>& targets)
             {
                 targets.clear();
+                if(_target)
                     targets.push_back(_target);
             }