ap_duplicate_listeners() ignored the return value of make_sock() for a
duplicated listener. On failure make_sock() logs the error and closes
the socket, but the loop carried on with the closed listener: with one
Listen the server started or restarted with fewer listeners, and with
several it failed on the closed descriptor with a misleading "Bad file
descriptor". Return the error so that the MPM reports "could not
duplicate listeners" with the original status.
PR: 70106
Submitted by: Xuqing Yang
GitHub: closes#861
git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1939304 13f79535-47bb-0310-9956-ffa450edef68