futility: updater: report flashrom error code

When flashrom execution failed, it is not very easy to debug what went
wrong especially when loading system active firmware (-r).
The log may say SUCCEED (or no obvious error) and updater simply reports
failure. Reporting the returned termination status should help.

BUG=chromium:943262
TEST=make futil; tests/futility/run_test_scripts.sh $(pwd)/build/futility
BRANCH=None

Change-Id: I4ea09b3d62ebf77eda98084accac582f841e7f7a
Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1545590
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-by: Edward O'Callaghan <quasisec@chromium.org>
1 file changed