datastore: unbreak build.
datastore: unbreak build.

A datastore example test relies on a non-deterministic ordering of Property
fields.

This change disables the Output: line so that this doesn't cause the
build to fail.

Change-Id: I7b2dcd257f35142c99fc489c602a94764e52edf5
Reviewed-on: https://code-review.googlesource.com/7991
Reviewed-by: Dave Day <4cba7a21e1f1fc896442779dcb55aeda6df97dfe@golang.org>

googleapis/google-cloud-go,michael-grosshans/google-cloud-go,googleapis/google-cloud-go,googleapis/google-cloud-go,michael-grosshans/google-cloud-go,googleapis/google-cloud-go