javascript: Fix up vgrunt after changes to the identity tool.
javascript: Fix up vgrunt after changes to the identity tool.

Change https://veyron-review.googlesource.com/#/c/3310/ modified the API
of the identity command-line tool, which broke these vgrunt-based tests.

Change-Id: I1530f21d5da05ab8c4adfe7c53790bc63c397fcd

vanadium/js,vanadium/js,vanadium/js,vanadium/js