[Autotest] Disable trying stateful update only in machine_install

As /etc/lsb-release does not have the rc# in cros version, it is
not sufficient to determine exactly which version is running in DUT.
machine_install should not try stateful update only. The _try_statefule_update
method is bypassed until bug 222238 is fixed.

BUG=chromium:222098
TEST=manually run in local machine

Change-Id: I9223874a21d294fa9c11974f289190e2e0313431
Reviewed-on: https://gerrit.chromium.org/gerrit/45917
Tested-by: Dan Shi <dshi@chromium.org>
Reviewed-by: Richard Barnette <jrbarnette@chromium.org>
Commit-Queue: Dan Shi <dshi@chromium.org>
1 file changed