Use new purge_by_orphaned method for binary_blobs

app/models/binary_blob/purging.rb

@@ -5,17 +5,13 @@ module Purging
 
     module ClassMethods
       def purge_timer
-        purge_queue(:scope)
+        purge_queue(:orphaned, 'resource')
       end
 
       def purge_window_size
         ::Settings.binary_blob.purge_window_size
       end
 
-      def purge_scope(_older_than = nil)
-        where(:resource_type => 'MiqQueue').where.not('resource_id in (select id from miq_queue)')
-      end
-
       def purge_associated_records(ids)
         BinaryBlobPart.where(:binary_blob_id => ids).delete_all
       end