Build on newer Node.js

Author: bergie

.travis.yml

@@ -2,7 +2,7 @@ language: node_js
 services:
 - rabbitmq
 node_js:
-- '4.2'
+- '6'
 before_install:
 - sudo apt-get update -qq
 - sudo apt-get install pkg-config cmake openssl libc-ares-dev