Fix rubocop complain on instance variable usage in module

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

ee/app/controllers/ee/projects/pipelines_controller.rb

@@ -6,10 +6,10 @@ module EE
       def security
         commit
 
-        if @pipeline.sast_artifact
+        if pipeline.sast_artifact
           render_show
         else
-          redirect_to pipeline_path(@pipeline)
+          redirect_to pipeline_path(pipeline)
         end
       end
     end