test__event.py: do not do kill(block=True) since blocking is default

--HG--
extra : transplant_source : %18%2C%D7%81%AC%D7Y%F4%5D%88%A9%E1%F7%1F%0BE-%D6%BC%D3

greentest/test__event.py

@@ -56,7 +56,7 @@ class TestAsyncResult(greentest.TestCase):
                 assert result is X, 'Nobody sent anything to event2 yet it received %r' % (result, )
         finally:
             t.cancel()
-            g.kill(block=True)
+            g.kill()
 
 
 class TestAsync_ResultAsLinkTarget(greentest.TestCase):