replace basetring/xrange

basetring --> six.string_types
xrange --> six.moves.xrange

Partial Implement: blueprint tempest-py33-support

Change-Id: Ia7ae4415d6d4ca9ee04e6735b2c6a6131c05a04f
diff --git a/tempest/common/glance_http.py b/tempest/common/glance_http.py
index 4503f13..b4ba933 100644
--- a/tempest/common/glance_http.py
+++ b/tempest/common/glance_http.py
@@ -21,6 +21,7 @@
 import json
 import posixpath
 import re
+from six import moves
 import socket
 import StringIO
 import struct
@@ -264,7 +265,7 @@
 
         # Also try Subject Alternative Names for a match
         san_list = None
-        for i in xrange(x509.get_extension_count()):
+        for i in moves.xrange(x509.get_extension_count()):
             ext = x509.get_extension(i)
             if ext.get_short_name() == 'subjectAltName':
                 san_list = str(ext)