Merge r1724847, r1725516 from trunk:

flush errors are TRACE1 in the core output filter now.



Remove APLOGNO after moving log message to
TRACE1 in r1724847.

Submitted by: covener, rjung
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1726018 13f79535-47bb-0310-9956-ffa450edef68