Fix bugs in autotest firmware_updateECBin

Fix the following bugs:
1. Some methods do not follow the new naming style.
2. New_ec_checker failed in step 3.
3. In some steps, delay of waiting for dev screen is not enough (caused by
    software sync) during ecfw_act=RW.

BUG=chrome-os-partner:35902
TEST=run firmware_updateECBin test

Change-Id: I6a0bad694c455b7bde8de9726a2e3bcf0bfeda0f
Reviewed-on: https://gerrit.chromium.org/gerrit/39459
Reviewed-by: Tom Wai-Hong Tam <waihong@chromium.org>
Commit-Ready: Chun-Ting Chang <ctchang@chromium.org>
Tested-by: Chun-Ting Chang <ctchang@chromium.org>
2 files changed