fix typo issue

Change-Id: I02d7a12e039620eebb836d863599e7dc3ad9d184
Signed-off-by: michael zhang <zhangcheng@rbcon.com>
Reviewed-on: http://reviews.cloudfoundry.org/13379
Tested-by: CI Master <cf-ci@rbcon.com>
Reviewed-by: Pin Xie <pxie@vmware.com>