Updates Travis to latest Ubuntu (#3187)
Updates Travis to latest Ubuntu (#3187)


adriancole/zipkin,twitter/zipkin,openzipkin/zipkin,openzipkin/zipkin,adriancole/zipkin,twitter/zipkin,twitter/zipkin,openzipkin/zipkin,openzipkin/zipkin,openzipkin/zipkin,twitter/zipkin,adriancole/zipkin,adriancole/zipkin