auto-t: increase wait time for blacklist test

This test was not reliably passing. Busy waiting is not really reliable,
but in this specific case its really the only option as the blacklist
must expire based on time.

autotests/testBSSBlacklist/connection_test.py

@@ -48,9 +48,11 @@ class Test(unittest.TestCase):
         psk_agent = PSKAgent("secret123")
         wd.register_psk_agent(psk_agent)
 
-        devices = wd.list_devices(1)
+        devices = wd.list_devices(2)
         device = devices[0]
 
+        devices[1].disconnect()
+
         condition = 'not obj.scanning'
         wd.wait_for_object_condition(device, condition)
 
@@ -110,8 +112,8 @@ class Test(unittest.TestCase):
         # Wait for the blacklist to expire (10 seconds)
         elapsed = time.time() - start
 
-        if elapsed < 11:
-            time.sleep(11 - elapsed)
+        if elapsed < 15:
+            wd.wait(15 - elapsed)
 
         device.disconnect()