message: drake: k/v iteration
diff: @@ -1749,8 +1749,8 @@ def command(cmd, cwd = None, stdout = None, env = None):
  def command_flatten(command, env = None):
  if env:
  - env_ = ['%s=%s' % (var, pipes.quote(str(env[var])))
  - for var in sorted(env.keys())]
  + env_ = ['%s=%s' % (var, pipes.quote(str(val)))
  + for var, val in sorted(env.items())]
  if PRETTY:
  env_ = ' \\\n '.join(env_) + ' \\\n'
  else:
  