If a Date response header was already set in the headers array,

If a Date response header was already set in the headers array,
this value was ignored in favour of the current time. This meant
that Date headers on proxied requests where rewritten when they
should not have been.
PR:		14376
Obtained from:
Submitted by:
Reviewed by:

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@99370 13f79535-47bb-0310-9956-ffa450edef68