[2823] Don't use private prefix in local scope

For one, it makes no sense (it won't be visible from outside the
function anyway), for another, it didn't work, because it was called
from different scope (inside the FailingStatsHttpd class) and mangling
the name wrongly.

src/bin/stats/tests/stats-httpd_test.py

@@ -651,13 +651,13 @@ class TestStatsHttpd(unittest.TestCase):
 
         """
         self.__mccs_closed = False
-        def __call_checker():
+        def call_checker():
             self.__mccs_closed = True
         class FailingStatsHttpd(MyStatsHttpd):
             def open_httpd(self):
                 raise stats_httpd.HttpServerError
             def close_mccs(self):
-                __call_checker()
+                call_checker()
         self.assertRaises(stats_httpd.HttpServerError, FailingStatsHttpd)
         self.assertTrue(self.__mccs_closed)