auto-t: fix testRSSIAgent after signal agent changes

The signal agent notifications were changed which breaks this test.
Specifically commit ce227e7b94 sends a notification when connected
which breaks the 'agent.calls' check. Since this check is done both
after connecting and once already connected the initial value may
be 1 or 0. Because of this that check was removed entirely.

autotests/testRSSIAgent/connection_test.py

@@ -56,7 +56,6 @@ class Test(unittest.TestCase):
             # at least) uses a moving-window average value over the last RSSI
             # measurements received from the driver and it changes gradually.
             # Normally 1 second is enough.
-            self.assertEqual(agent.calls, 0)
             for centre, level in rssi_pairs:
                 rule.signal = centre
                 agent.level = -1