cmd/coordinator: fix pinging of dashboard to show in-progress builds
cmd/coordinator: fix pinging of dashboard to show in-progress builds

The blue in-progress gophers have been missing in build.golang.org
because the magic log span strings changed.

Change-Id: I702883d8a6f6eea31aaaaa25ebe10e929992a677
Reviewed-on: https://go-review.googlesource.com/22747
Reviewed-by: Ross Light <dfccc06f14414bff5a59be7fc90abf4404b47fc8@google.com>

golang/build,golang/build,golang/build,golang/build