Add kombu in dev-requirements.txt so it is picked up by travis-ci.
Add kombu in dev-requirements.txt so it is picked up by travis-ci.

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