Galaxy: remove /galaxy/config/plugins
Galaxy: remove /galaxy/config/plugins

This folder uses more than 700MB. As client
stuff is already stored in /galaxy/static, we can
probably safely remove this.

bgruening/docker-galaxy-stable,chambm/docker-galaxy-stable,chambm/docker-galaxy-stable,bgruening/docker-galaxy-stable,chambm/docker-galaxy-stable,bgruening/docker-galaxy-stable