dashboard/app: fix tests hang
dashboard/app: fix tests hang

This is ugly but without this go test hangs with:

panic: Metadata fetch failed for 'instance/attributes/gae_backend_version':
	Get http://metadata/computeMetadata/v1/instance/attributes/gae_backend_version:
	dial tcp: lookup metadata on 127.0.0.1:53: no such host

It's unclear what's the proper fix for this.

It used to work for me for ridiculous reasons only:
somebody provided metadata host which returned errors,
but since nobody cares what's in the returned response
and no error checking whatsoever, it somehow did not crash...

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