Typos in config comments.

Backports of r290940, r713575 and r732816
from 2.4.x resp. r1489879 from 2.2.x.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@1489881 13f79535-47bb-0310-9956-ffa450edef68