Use short lived pool to avoid memory leaks

Remove the comment about binding upstream and downstream connections. It
seems to be obsolete since r104604, r104605, r105108.

Also avoid allocating memory if we are not handling the connection.

PR: 52275
Submitted by: Naohiro Ooiwa <naohiro ooiwa miraclelinux com>, Stefan Fritsch

Submitted by: sf
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1368450 13f79535-47bb-0310-9956-ffa450edef68