Fixed issue with automatic HipChat configuration.

This fixes an issue where the template attempts to configure a HipChat room in .travis.yml even when no API key or HipChat room were provided.
when you don't enter a value, is `hipchat_api_key` an empty string or nil?

do we have a similar issue with the `new_relic_license_key` and `honeybadger_api_key` input?