diff --git a/plugins/provisioners/docker/config.rb b/plugins/provisioners/docker/config.rb
index 644b1f673..4eb1a723f 100644
--- a/plugins/provisioners/docker/config.rb
+++ b/plugins/provisioners/docker/config.rb
@@ -22,8 +22,6 @@ module VagrantPlugins
       end
 
       def build_images(*images)
-        possible_options = @build_options.keys
-
         @build_images = images.map do |image|
           image.values_at(:path, :args)
         end