add help (-h/--help/help) to fetch.

TBR=iannucci@chromium.org, maruel@chromium.org
BUG=

Review URL: https://codereview.chromium.org/13586003

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@192135 0039d316-1c4b-4281-b951-d872f2087c98

fetch.py

@@ -156,6 +156,8 @@ def handle_args(argv):
   """Gets the recipe name from the command line arguments."""
   if len(argv) <= 1:
     usage('Must specify a recipe.')
+  if argv[1] in ('-h', '--help', 'help'):
+    usage()
 
   def looks_like_arg(arg):
     return arg.startswith('--') and arg.count('=') == 1