Avoid false alarm when testing kamaki threads

The false alarm in caused when testing kamaki threads that run too
fast to catch them in an unfinished state. The "assert thread as
unfinished" check fails in that case, although nothing is wrong
with the functionality.

kamaki/clients/test.py

@@ -236,10 +236,10 @@ class SilentEvent(TestCase):
             t.start()
 
         for i in range(4):
-            self.assertTrue(threads[i].is_alive())
+            if threads[i].is_alive():
+                threads[i].join()
+                self.assertFalse(threads[i].is_alive())
             self.can_finish = i
-            threads[i].join()
-            self.assertFalse(threads[i].is_alive())
 
     def test_value(self):
         threads = [self.SE(self.thread_content, i) for i in range(4)]