delete aspect_visibilities when deleting the shareable

lib/diaspora/shareable.rb

@@ -8,7 +8,7 @@ module Diaspora
   module Shareable
     def self.included(model)
       model.instance_eval do
-        has_many :aspect_visibilities, as: :shareable, validate: false
+        has_many :aspect_visibilities, as: :shareable, validate: false, dependent: :delete_all
         has_many :aspects, through: :aspect_visibilities
 
         has_many :share_visibilities, as: :shareable, dependent: :delete_all