bugfix editing variants

app/models/product.rb

@@ -352,6 +352,7 @@ class Product < ActiveRecord::Base
         @products_variant.is_parent = false
         @products_variant.sku = sku + (index + 1).to_s + "A"
         @products_variant.category_ids = category_ids
+        @products_variant.barcode = ''
         attrs_json = {}
         if combination.is_a?(Array)
           combination.each do |attrib|