setup.py: Silence warning about discontinued test_suite argument
diff --git a/setup.py b/setup.py
index 231d756..02cdd69 100644
--- a/setup.py
+++ b/setup.py
@@ -152,5 +152,4 @@
         if 'bdist_wheel' in sys.argv else
         []
     ),
-    test_suite='usb1.testUSB1',
 )