ci/lava: support being used with ZeroMQ < 4.2
ci/lava: support being used with ZeroMQ < 4.2

PyZMQ needs to be built against ZeroMQ 4.2+ to have heartbeat support.
That's the case in Debian stretch, but not with upstream(pip) PyZMQ,
which bundles ZeroMQ 4.1.

terceiro/squad,terceiro/squad,terceiro/squad,terceiro/squad