[master] tweak TestOSEnv just like stats-httpd_test to suppress log leak

also renamed the stats-httpd_test counterpart; it seemed to be tenntatively
named and left unchanged, so doesn't really make sense for what it does.

these should be trivial, so I'm committing this at my discretion.

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

@@ -1104,7 +1104,7 @@ class TestStatsHttpd(unittest.TestCase):
         self.assertEqual('@description', stats_xsl[2].find('%sif' % nst).attrib['test'])
         self.assertEqual('@description', stats_xsl[2].find('%sif/%svalue-of' % ((nst,)*2)).attrib['select'])
 
-class Z_TestStatsHttpdError(unittest.TestCase):
+class Z_TestOSEnv(unittest.TestCase):
     def test_for_without_B10_FROM_SOURCE(self):
         # Note: this test is sensitive due to its substantial side effect of
         # reloading.  For exmaple, it affects tests that tweak module

src/bin/stats/tests/stats_test.py

@@ -1401,7 +1401,10 @@ class TestStats(unittest.TestCase):
              stat.statistics_data['Init'],
              {'boot_time': self.const_default_datetime})
 
-class TestOSEnv(unittest.TestCase):
+class Z_TestOSEnv(unittest.TestCase):
+    # Running this test would break logging setting.  To prevent it from
+    # affecting other tests we use the same workaround as
+    # Z_TestStatsHttpdError.
     def test_osenv(self):
         """
         test for the environ variable "B10_FROM_SOURCE"