Switch Travis to "language: bash" (which will actually avoid all the "ruby" output once they deploy the change)

See also https://github.com/travis-ci/travis-ci/issues/2856 and https://github.com/travis-ci/travis-build/pull/306
Merge pull request #253 from infosiftr/bash-travis

Switch Travis to "language: bash" (which will actually avoid all the "ruby" output once they deploy the change)