res:dock:: fix dock cannot be shown after dde-session-daemon is restarted.

tower:https://tower.im/projects/8f19f0bf0e754f0b82ef2c24bc230973/todos/1f07dd7cb0724948bad734ae6ad98274/
Change-Id: I5d3a4bdddb94ee469d951f244017fd247e132924