(#12361) Remove masterlog option

Pull the `masterlog` configuration option as it is unused and causes confusion.
Also, re-word the description of a test in `webrick_spec.rb` as it is testing
the behavior of `masterhttplog` and not `masterlog`.
Merge pull request #1686 from Sharpie/12361-remove-masterlog-setting

(#12361) Remove masterlog option