cmd/coordinator/buildongce: set Scopes for DefaultClient

Otherwise it doesn't work.

Maybe it worked for Evan because he was on a GCE VM with the
right scopes itself. I am not.

Change-Id: Id29a3256a71c732cd9d63055c51b80a9f77b4211
Reviewed-on: https://go-review.googlesource.com/18982
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
1 file changed