Update StringIO to use six

It's StringIO.StringIO in python2 and io.StringIO in python3,
but six.StringIO everywhere.

Change-Id: Ief0b091b716e3ea6224c0ac374a6066f0270bebc
diff --git a/jeepyb/cmd/openstackwatch.py b/jeepyb/cmd/openstackwatch.py
index 1064fc7..c9d6a54 100644
--- a/jeepyb/cmd/openstackwatch.py
+++ b/jeepyb/cmd/openstackwatch.py
@@ -23,8 +23,8 @@
 
 __author__ = "Chmouel Boudjnah <chmouel@chmouel.com>"
 
+import six
 from six.moves import configparser
-import cStringIO
 import datetime
 import json
 import os
@@ -127,7 +127,7 @@
         time.sleep(1)
 
     client.put_object(cfg['container'], objectname,
-                      cStringIO.StringIO(content))
+                      six.StringIO(content))
 
 
 def generate_rss(content, project=""):
diff --git a/jeepyb/cmd/update_blueprint.py b/jeepyb/cmd/update_blueprint.py
index 0649dff..c1fd98a 100644
--- a/jeepyb/cmd/update_blueprint.py
+++ b/jeepyb/cmd/update_blueprint.py
@@ -18,10 +18,10 @@
 # corresponding Launchpad blueprints with links back to the change.
 
 import argparse
+import six
 from six.moves import configparser
 import os
 import re
-import StringIO
 import subprocess
 
 from launchpadlib import launchpad
@@ -54,7 +54,7 @@
         for line in conf.readlines():
             text = "%s%s" % (text, line.lstrip())
 
-    fp = StringIO.StringIO(text)
+    fp = six.StringIO(text)
     c = configparser.ConfigParser()
     c.readfp(fp)
     return c
diff --git a/jeepyb/gerritdb.py b/jeepyb/gerritdb.py
index 963f997..b362240 100644
--- a/jeepyb/gerritdb.py
+++ b/jeepyb/gerritdb.py
@@ -14,9 +14,9 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import six
 from six.moves import configparser
 import os
-import StringIO
 
 
 GERRIT_CONFIG = os.environ.get(
@@ -34,7 +34,7 @@
     for line in open(filename, "r"):
         text += line.lstrip()
 
-    fp = StringIO.StringIO(text)
+    fp = six.StringIO(text)
     c = configparser.ConfigParser()
     c.readfp(fp)
     return c