Add a missing break in AuraEffect::CalculateSpellMod. Thanks to vlad852 for pointing out.

src/server/game/Spells/Auras/SpellAuraEffects.cpp

@@ -903,6 +903,7 @@ void AuraEffect::CalculateSpellMod()
                 default:
                     break;
             }
+            break;
         case SPELL_AURA_ADD_FLAT_MODIFIER:
         case SPELL_AURA_ADD_PCT_MODIFIER:
             if (!m_spellmod)