Sort the list of tools shown by cit.py's help message

(it looks nicer)

BUG=

Review URL: https://codereview.chromium.org/1682293002

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@298842 0039d316-1c4b-4281-b951-d872f2087c98

cit.py

@@ -77,7 +77,7 @@ def get_available_tools():
   for root, _, files in os.walk(starting):
     if '__main__.py' in files:
       tools.append(root[len(starting)+1:].replace(os.path.sep, '.'))
-  return tools
+  return sorted(tools)
 
 
 def run(args):