FuturePoolJavaFutureConverter is not compatible w/ twitter-util 19.1.0

[jcohen]

This commit in twitter-util removed NonFatal from com.twitter.util in favor of the version from scala.util.control.

Unfortunately FuturePoolJavaFutureConverter (and perhaps other places as well) relies on the version from com.twitter.util (which no longer exists) leading to NoClassDefFoundError exceptions at runtime.

[johnynek]

Happy to take a PR to update this.

[jcohen]

Thanks for merging that @johnynek! Would it be possible to push a release with this fix?