hadley/devtools — pull request #617 by lmullen (2014-10-10 15:32:31+00:00)
Title: Use after_failure not on_failure

Travis documentation wants the key after_failure not on_failure:
http://docs.travis-ci.com/user/build-configuration/

This key has been updated at craigcitro/r-travis:
https://github.com/craigcitro/r-travis/blob/master/sample.travis.yml