fix(travis, semantic-release): Change node version to 5 in travis.yml

This is an experiment to see if it fixes semantic release.

Author: dalelotts

.travis.yml

@@ -6,7 +6,7 @@ cache:
 notifications:
   email: false
 node_js:
-  - '6'
+  - '5'
 before_install:
   - export DISPLAY=:99.0
   - sh -e /etc/init.d/xvfb start