mod_brotli: Fix leftovers from mod_deflate or incorrect directives in

the "Serving pre-compressed content" section of the docs.

Generally speaking, this section would benefit from a rewrite pointing
out how to configure a mod_deflate + mod_brotli configuration with
precompressed contents, but for now at least fix the mistakes in the
configuration.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1790871 13f79535-47bb-0310-9956-ffa450edef68