factory_install: Fix typos. There are typos in factory_install.sh and they will cause cros_payload always fails to install complete script and firmware. Fix them. BUG=b:65270817 TEST=none Change-Id: I4dc15c9df03a1fabfe644b17751dc9b4c713c2ee Reviewed-on: https://chromium-review.googlesource.com/647956 Commit-Ready: Youcheng Syu <[email protected]> Tested-by: Youcheng Syu <[email protected]> Reviewed-by: Hung-Te Lin <[email protected]> Reviewed-by: Marco Chen <[email protected]>