Changing any settings is prevented when project has existing currency (…

…#1292)

ihatemoney/forms.py

@@ -195,7 +195,7 @@ def validate_default_currency(self, field):
             raise ValidationError(msg)
         if (
             project is not None
-            and field.data != CurrencyConverter.no_currency
+            and field.data != project.default_currency
             and project.has_bills()
         ):
             msg = _(