Removes curl as it is now in the parent image
Removes curl as it is now in the parent image

See https://github.com/openzipkin/docker-jre-full/commit/6b53fb7abf2f7f48e878f2e1dfd90bbe013e384a

openzipkin/docker-zipkin,itszero/docker-zipkin,openzipkin/docker-zipkin,itszero/docker-zipkin