futility: update: Skip TPM check if tpm_fwver is not valid.

Ideally we should fail if `tpm_fwver` can't be retrieved, but if an user can
run the updater then his system is already up so it's more likely to be a
vboot library issue (especially in early proto devices) that the crossystem
values were not reported correctly.

As a result, it seems more reasonable to skip checking TPM anti-rollback if
`tpm_fwver` can't be retrieved.

TEST=make futil; tests/futility/run_test_scripts.sh $(pwd)/build/futility

Change-Id: I7b6bf72531edb334a465c730fe8b3fbafa469b3a
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1238099
Reviewed-by: Joel Kitching <kitching@chromium.org>
2 files changed