Remove six.moves module

Python 3 reorganized the standard library and moved several functions to
different modules. Six provides a consistent interface to them through the
fake six.moves module.

But six.StringIO is an alias for StringIO.StringIO in Python 2 and
io.StringIO in Python 3. So we don't need six.moves.StringIO() any more,
we use six.StringIO() directly.

Here is links :http://pythonhosted.org/six/#module-six.moves

Change-Id: I44dbe915820ba4b5ffc0e34812fadc3d905542d1

senlinclient/tests/unit/test_utils.py

@@ -20,14 +20,13 @@ from heatclient.common import template_utils
 from senlinclient.common import exc
 from senlinclient.common.i18n import _
 from senlinclient.common import utils
-from six import moves
 
 
 class CaptureStdout(object):
     """Context manager for capturing stdout from statements in its block."""
     def __enter__(self):
         self.real_stdout = sys.stdout
-        self.stringio = moves.StringIO()
+        self.stringio = six.StringIO()
         sys.stdout = self.stringio
         return self