director's app_cluster.db test file update
[plugins] director: refactor code to expose RequestNotes to other flow exposed functions, too.

We required that to allow things like custom flow functions to disable
object caching, for example.

This refactorization however still makes sense, as we now deal with one
handle internally for to-be-served HTTP requests: RequestNotes.

We may come up with a better name later.
[plugins] director: enables director.cache.bypass() flow function
[http] HttpStatus: typo fix for 'GatewayTimeout'