Repair version deprecation warning

I kept getting the deprecation warning

    Warning: Scope(Class[Postgresql::Server]): Passing "version" to postgresql::server is deprecated; please use postgresql::globals instead.

when using the `postgresql::server` class.

This happened regardless if I passed a `version` parameter to the class or not.

Since I do not know how to test for deprecation warnings, I could not add a test for that. I also refrained from testing wether the version passed to the class is actually taking effect, because this is a deprecated way of setting the version.

If needed, I can add try to add a failing test for the state before this patch. Personally, I do not want to endorse a deprecated API by adding a test using it.