test__pool.py: do not leak greenlets out of test case

--HG--
extra : transplant_source : %D4%9E%3F%5BS%D4%93k%A5a%A7%F2%DD%90FQ%25%5C%80%A6

greentest/test__pool.py

@@ -286,7 +286,9 @@ class TestJoinSleep(greentest.GenericWaitTestCase):
     def wait(self, timeout):
         p = pool.Pool()
         g = p.spawn(gevent.sleep, 10)
+        try:
             p.join(timeout=timeout)
+        finally:
             g.kill()
 
 
@@ -295,7 +297,9 @@ class TestJoinSleep_raise_error(greentest.GenericWaitTestCase):
     def wait(self, timeout):
         p = pool.Pool()
         g = p.spawn(gevent.sleep, 10)
+        try:
             p.join(timeout=timeout, raise_error=True)
+        finally:
             g.kill()