test/py: Drop assigning ubman to cons

Now that we have a shorter name, we don't need this sort of thing. Just
use ubman instead.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/py/tests/test_handoff.py b/test/py/tests/test_handoff.py
index c0cfa3b..becd7d7 100644
--- a/test/py/tests/test_handoff.py
+++ b/test/py/tests/test_handoff.py
@@ -10,6 +10,5 @@
 @pytest.mark.buildconfigspec('spl')
 def test_handoff(ubman):
     """Test that of-platdata can be generated and used in sandbox"""
-    cons = ubman
-    response = cons.run_command('sb handoff')
+    response = ubman.run_command('sb handoff')
     assert ('SPL handoff magic %x' % TEST_HANDOFF_MAGIC) in response