UserDefinedEnum variables in UserDefinedStructs aren't properly updated when the enumerations are reordered.

UserDefinedEnum variables in UserDefinedStructs aren't properly updated when the enumerations are reordered. FEnumEditorUtils::BroadcastChanges fixes up Blueprints but not UserDefinedStructs. 

• Create a UserDefinedEnum (MyEnum) and add a few enumerations {Zero, One, Two}
• Create a UserDefinedStruct (MyStruct) and add a variable of type MyEnum
• Set a default value for the MyEnum variable to Zero
• Reorder the enumerations by moving "Two" up to be the first entry in MyEnum
• Notice that the default value in MyStruct changes from "Zero" to "Two"