Accounts for Jenkins API returning 403

For installations of Jenkins where login is required a 403 response is returned from the Jenkins API when requesting http://your-jenkins-server.com/api/json. Currently, the ``jenkins::server`` recipe checks that API URL and blocks the chef run from progressing until a 200 or 302 are returned. This change allows the ``jenkins::server`` recipe to continue running if the Jenkins API returns a 403, which is a valid response.