Fix Scoping Problems with "rails_base_uri" Parameter

This pull request fixes a bug where the "rails_base_uri" parameter wasn't listed in the base module nor was it being passed into the "::passenger" sub-module.  This also corrects the reference to this variable in in the template- I'm not sure why, but I expect it's due to the template being used by the Apache module- I think the variables in the dashboard scope fall out.

I am working within Puppet 3.2.4, I would expect this fix to work in 2.7.

>
> I am still pretty green operating GitHub- hopefully I'm doing this pull 
> request correctly. Please do let me know if I've screwed it up or if I 
> can do something different- I have additional fixes for this module I'd 
> like to contribute
>
> Thanks!  
>
> -Michael