tools: ratbagctl.test: assert on the ratbagd process

If we could not start the process, there is a high chance we are running
the tests against a different ratbagd implementation so there is no point.

Also, an exception will get raised later during the tear down of the
module saying that "'NoneType' object has no attribute 'terminate'".

This is less than ideal to notify that the process has not been started.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>

tools/ratbagctl.test.in

@@ -564,6 +564,8 @@ def setUpModule():
 
     ratbagd_process = toolbox.start_ratbagd()
 
+    assert ratbagd_process is not None
+
     ratbagd = toolbox.open_ratbagd(ratbagd_process)
     assert ratbagd is not None