Revert "Remove delete digitals on soft delete of variant"

This reverts commit d23462fadb.

app/models/spree/variant_decorator.rb

@@ -1,8 +1,20 @@
 Spree::Variant.class_eval do
+  
   has_many :digitals, :dependent => :destroy
+  after_save :destroy_digital, :if => :deleted?
   
   # Is this variant to be downloaded by the customer?
   def digital?
     digitals.present?
   end
+  
+  private
+  
+  # Spree never deleted Digitals, that's why ":dependent => :destroy" won't work on Digital.
+  # We need to delete the Digital manually here as soon as the Variant is nullified.
+  # Otherwise you'll have orphan Digitals (and their attached files!) associated with unused Variants. 
+  def destroy_digital
+    digitals.map &:destroy
+  end
+
 end