[login_manager] Start chrome with opencryptoki flag if user enables the lab

Change-Id: I0cfffd6abe2528bb92debb4aea38fd4bd4055cb5

R=cmasone@chromium.org
BUG=chromium-os:12416
TEST=
default mode, no flag added
with file, --load-opencryptoki added

Review URL: http://codereview.chromium.org/6877059
1 file changed