tests: add sleep after flow timeouts

For normal flow-mods we can use the barrier message to find out when the change
has made it to the datapath. This isn't the case with timeouts, because the
update isn't associated with any controller connection. When tests are run in
short succession the timed out flow may still exist in the datapath when the
next test starts.
diff --git a/tests/detailed_contr_sw_messages.py b/tests/detailed_contr_sw_messages.py
index a32251d..824692f 100644
--- a/tests/detailed_contr_sw_messages.py
+++ b/tests/detailed_contr_sw_messages.py
@@ -628,6 +628,8 @@
         self.assertEqual(1, response.duration_sec,
                          'Flow was not alive for 1 sec')
 
+        sleep(1)
+
 
 class Outport2(base_tests.SimpleDataPlane):
 
@@ -710,6 +712,8 @@
         self.assertEqual(1, response.duration_sec,
                          'Flow was not alive for 1 sec')
 
+        sleep(1)
+
 
 class FlowTimeout(base_tests.SimpleDataPlane):
   
@@ -761,6 +765,8 @@
         # Verify no entries in the table
         verify_tablestats(self,expect_active=0)
 
+        sleep(1)
+