Fixing ruby version

With this commit, I'm adjusting the command used to start Kibana in the upstart script, to ensure the proper version of ruby is used. ruby1.9.1 is installed, and then the bundle of gems are installed for ruby1.9.1, so the daemon startup command will force using ruby1.9.1 too now.  1.9.1 is an attribute, so that it can be changed in one place as necessary.
-N