robot: change the message order

We need to show preparing message before calling LoadDevice, so operator
can know the robot is under movement.

BUG=chromium:613117
TEST=None

Change-Id: I667ec087bb7cd4f4c8a4cabc529d25886726098f
Reviewed-on: https://chromium-review.googlesource.com/354103
Commit-Ready: Shun-Hsing Ou <shunhsingou@chromium.org>
Tested-by: Shun-Hsing Ou <shunhsingou@chromium.org>
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
1 file changed