[NaCl SDK] Add keyboard interrupt handlers for python scripts

native_client_sdk/src/tools/oshelpers.py

 #!/usr/bin/env python
 # Copyright (c) 2012 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.
 
 import fnmatch
 import glob
 import optparse
 import os
 import posixpath
@@ skipping 507 matching lines @@
   'zip': Zip,
   'which': Which,
 }
 
 
 def main(args):
   if not args:
     print 'No command specified'
     print 'Available commands: %s' % ' '.join(FuncMap)
     return 1
-  func = FuncMap.get(args[0])
+  func_name = args[0]
+  func = FuncMap.get(func_name)
   if not func:
-    print 'Do not recognize command: ' + args[0]
+    print 'Do not recognize command: %s' % func_name
     print 'Available commands: %s' % ' '.join(FuncMap)
     return 1
-  return func(args[1:])
+  try:
+    return func(args[1:])
+  except KeyboardInterrupt:
+    print '%s: interrupted' % func_name
+    return 1
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))