proxy_connect_handler: fix use of APLOGNO() (backport r1375407).

Submitted by: jorton
Reviewed/backported by: sf, fuankg



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1386952 13f79535-47bb-0310-9956-ffa450edef68