Cleanup unused imports in lwr.util.
Cleanup unused imports in lwr.util.

natefoo/pulsar,galaxyproject/pulsar,jmchilton/pulsar,jmchilton/lwr,ssorgatem/pulsar,jmchilton/lwr,ssorgatem/pulsar,galaxyproject/pulsar,natefoo/pulsar,jmchilton/pulsar