Add a warning if the current version of python is not 2.5

gcl.py

-#!/usr/bin/python
-# Copyright (c) 2010 The Chromium Authors. All rights reserved.
+#!/usr/bin/env python
+# Copyright (c) 2011 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """\
 Wrapper script around Rietveld's upload.py that simplifies working with groups
 of files.
 """
 
 import getpass
 import optparse
 import os
 import random
 import re
 import string
 import subprocess
 import sys
 import tempfile
 import time
 from third_party import upload
 import urllib2
 
 try:
   import simplejson as json  # pylint: disable=F0401
 except ImportError:
   try:
-    import json
-    # Some versions of python2.5 have an incomplete json module.  Check to make
-    # sure loads exists.
-    # pylint: disable=W0104
-    json.loads
-  except (ImportError, AttributeError):
+    import json  # pylint: disable=F0401
+  except ImportError:
     # Import the one included in depot_tools.
     sys.path.append(os.path.join(os.path.dirname(__file__), 'third_party'))
     import simplejson as json  # pylint: disable=F0401
 
 import breakpad  # pylint: disable=W0611
 
 # gcl now depends on gclient.
 from scm import SVN
 
 import fix_encoding
@@ skipping 1409 matching lines @@
       raise
     print >> sys.stderr, (
         'AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
         'and retry or visit go/isgaeup.\n%s') % (e.code, str(e))
     return 1
 
 
 if __name__ == "__main__":
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))