board_status.sh add non-fatal test_cmd

- add a non-fatal option to test_cmd.

Change-Id: If74693ea7ec8ea24104d5836e4c24bfb135ef0e1
Signed-off-by: Martin Roth <martin.roth@se-eng.com>
Reviewed-on: http://review.coreboot.org/6257
Tested-by: build bot (Jenkins)
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Reviewed-by: David Hendricks <dhendrix@chromium.org>