Move restoration of the os.environ object into the context manager where it belongs

Lib/test/test_httpservers.py

@@ -60,7 +60,6 @@ class BaseTestCase(unittest.TestCase):
         self.lock.release()
         self.thread.stop()
         os.environ.__exit__()
-        os.environ = os.environ._environ
 
     def request(self, uri, method='GET', body=None, headers={}):
         self.connection = httplib.HTTPConnection('localhost', self.PORT)

Lib/test/test_support.py

@@ -576,6 +576,7 @@ class EnvironmentVarGuard(UserDict.DictMixin):
                     del self._environ[k]
             else:
                 self._environ[k] = v
+        os.environ = self._environ
 
 
 class DirsOnSysPath(object):