Add Ruby 2.1.1 to Travis build

In the process, allow failures from Ruby 2.1.0 due to:

    https://github.com/travis-ci/travis-ci/issues/2220

Change-Id: I4bbe1d4073f2a5fa92c6d1ff6cec1889a7ef96ab
Reviewed-on: http://gerrit.causes.com/37741
Tested-by: jenkins <jenkins@causes.com>
Reviewed-by: Shane da Silva <shane@causes.com>