Make unit tests be skipped if no network.

The unit tests access the flickr api. If external network
access is not allowed, this isn't going to work.

The Flickr blacklister thing considers inaccessible api to
mean image is "ok", which seems kind of odd, but separate issue.

Bug: 66938
Change-Id: If9de79209cf238c84b81e3af3dffbfcfd73328ed
Merge "Make unit tests be skipped if no network."