[201811 sub module] advance utilitie sub module (#2695)

Submodule src/sonic-utilities 2fe01fe..9d9aaa0:
  > [warm/fast reboot] setup control plane assistant when available (#487)
  > [reboot script] add -h, -? options (#484)

Signed-off-by: Ying Xie <ying.xie@microsoft.com>