Enforce python 2.6 or later.

TBR=bevc@chromium.org
BUG=
TEST=


Review URL: http://codereview.chromium.org/9178027

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@123276 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/git_cl.py b/git_cl.py
index 463b6c8..c967d8f 100755
--- a/git_cl.py
+++ b/git_cl.py
@@ -1449,6 +1449,11 @@
 def main(argv):
   """Doesn't parse the arguments here, just find the right subcommand to
   execute."""
+  if sys.hexversion < 0x02060000:
+    print >> sys.stderr, (
+        '\nYour python version %s is unsupported, please upgrade.\n' %
+        sys.version.split(' ', 1)[0])
+    return 2
   # Reload settings.
   global settings
   settings = Settings()