delete unused variable in test

theano/gof/tests/test_vm.py

@@ -230,9 +230,7 @@ if run_memory_usage_tests:
             a = cuda.CudaNdarray(n)
             a.sum()
             assert c == sys.getrefcount(n)
-            # This is to confuse flake8
-            a = a
-            del a
+            
             if not i % 1000:
                 print('.', end=' ')
                 print(gc.collect(), end=' ')