Merge r1386913, r1388825 from trunk:

Revert r1371878 --  default configuration changes that drop the DNT
header from IE10.

See:
  Message-ID: <CALK=YjMGPNHBqNiad-ghzcEzxDovQgYOpjpSSyXmN=r74v43qg@mail.gmail.com>
  PR 53845



Keep this in, but commented out: also provide a little
more background/rationale. This, hopefully, satisfies both
ends of the debate: we don't "assume" that everyone who
uses this browser didn't make the specific choice, but
we allow for admins who care about DNT and want to either
  1. Make a statement
  2. Force adherence to the standard
to easily do so.
Submitted by: covener, jim
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1389261 13f79535-47bb-0310-9956-ffa450edef68