Core/Spells: Fix Unstable Affliction

Closes #94
Closes #1244
Closes #1528

src/server/game/Entities/Unit/Unit.cpp

@@ -3714,11 +3714,14 @@ void Unit::RemoveAurasDueToSpellByDispel(uint32 spellId, uint64 casterGUID, Unit
                     // Unstable Affliction (crash if before removeaura?)
                     if (aura->GetSpellProto()->SpellFamilyFlags[1] & 0x0100)
                     {
+                        Unit* caster = aura->GetCaster();
+                        if (!caster)
+                            break;
                         if (AuraEffect const* aurEff = aura->GetEffect(EFFECT_0))
                         {
                             int32 damage = aurEff->GetAmount() * 9;
                             // backfire damage and silence
-                            dispeller->CastCustomSpell(dispeller, 31117, &damage, NULL, NULL, true, NULL, NULL, aura->GetCasterGUID());
+                            caster->CastCustomSpell(dispeller, 31117, &damage, NULL, NULL, true, NULL, aurEff);
                         }
                     }
                     break;

src/server/game/Spells/SpellMgr.cpp

@@ -3942,6 +3942,11 @@ void SpellMgr::LoadSpellCustomAttr()
             spellInfo->AttributesEx3 |= SPELL_ATTR3_CAN_PROC_WITH_TRIGGERED;
             ++count;
             break;
+        case 31117: // Unstable Affliction
+            // this attribute currently makes spell to ignore resilience and absorbs
+            spellInfo->AttributesEx4 &= ~SPELL_ATTR4_FIXED_DAMAGE;
+            ++count;
+            break;
         case 16007: // Draco-Incarcinatrix 900
             // was 46, but effect is aura effect
             spellInfo->EffectImplicitTargetA[0] = TARGET_UNIT_NEARBY_ENTRY;