mod_watchdog: Enable at --enable-modules=most for mod_proxy_hcheck

Backports: r1749924
Submitted by: wrowe
Reviewed by: rpluem, ylavic



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1750255 13f79535-47bb-0310-9956-ffa450edef68