Attributes with same labels lead to conflict

[dimonixx]

The system contains some System attributes, that must always be present in an Attribute Family. If we create or import an attribute with the an existing label (for example SKU)
we'll always get an error when saving an attribute family. Because on the form the original Names attribute won't be present anymore.

This can be also reproduced on the orocommerce demo system.

In our case the sku attribute has Art.-Nr. label and we imported an attribute from customer´s data with another code but the same label Art.-Nr. , after this we could not save any attribute family in the admin.