dashscrape: use commit date in JSON output
dashscrape: use commit date in JSON output

The dashboard JSON output recently added the commit date to the JSON
format, which means it's no longer necessary to map revisions to
commit dates locally or to have a clone of the git repository around
to do so.

aclements/go-misc,aclements/go-misc,aclements/go-misc,aclements/go-misc,aclements/go-misc