--always-reinstall-workers option not working

[jfischer]

The --always-reinstall-workers option on the datablox-master script should force a reinstall of datablox on worker nodes, not reusing any existing code. This seems to be broken, as some of my tests picked up an old version of the code. I think it could be due to the engage directory (created by expanding engage-dist.tar.gz). Also need to verify that rsync will really overwrite the old version of the engage-dist.tar.gz file.