channeldb/migration_01_to_11: remove unused code

channeldb/migration_01_to_11/codec.go

@@ -48,12 +48,6 @@ type UnknownElementType struct {
 	element interface{}
 }
 
-// NewUnknownElementType creates a new UnknownElementType error from the passed
-// method name and element.
-func NewUnknownElementType(method string, el interface{}) UnknownElementType {
-	return UnknownElementType{method: method, element: el}
-}
-
 // Error returns the name of the method that encountered the error, as well as
 // the type that was unsupported.
 func (e UnknownElementType) Error() string {