How do I remove all references to the Sample DB when using the Forena reports module on a server without PDO Sqllite?
Quote from Dave's (Forena maintainer) comment in a related Support Issue:


  ... You might uncheck permissions associated with accessing sample reports to make sure other users don't see this error.


Using this approach you should be OK when upgrading to future versions.

Disclosure: I'm a co-maintainer of Forena (and contributed quite a bit of the content of that forena_help repo you seem to be strugling with).