factory_install.conf: Find correct console for output.

For headless devices, we want to find right console (or an empty log file) to
start factory installation.

BUG=chromium:443972
TEST=Boots factory installer and see messages on tty1 as usual.
     Boots factory installer on headless devices without tty1.

Change-Id: Ib806cc43ae2baf62e6c850c15a100b41b9c026af
Reviewed-on: https://chromium-review.googlesource.com/246004
Reviewed-by: Vic Yang <victoryang@chromium.org>
Commit-Queue: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
1 file changed