error on default shipping methods when using "add to store"

When you convert a page node to a shippable product using the “add to store” buttom, the system shows you the checklist of avaible shipping methods with unchecked options as default value.

If you submit the node with these default unchecked options and later you try to edit by second, you’ll see all the shipping methods as cheched options but in true they are not shipping methods alowed on the data base. If you cancel the submiting you will think shipping methods are allowed to your product but the store doesn’t give you the shipping option when you try to make a purchase.

These patch solve the problem but I think it would be better if the first time you edit the node all the shipping methods were checked as default option.

This problem is not didn’t happen when you create a new “shippable product” node and not a conversión from another type of node.

I have tested this patch for the e-commerce 4.7.x-2.1 version.