Merge r1598946, r1602989 from trunk:

Fix computation of the size of 'struct sockaddr_un' when passed to 'connect()'.
Use the same logic as the one in ' in 'proxy_util.c'.


mod_proxy: Don't limit the size of the connectable Unix Domain Socket paths.
Since connect() to UDS path is used at several places, introduce
ap_proxy_connect_uds() in proxy_util.

Submitted by: jailletc36, ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1651081 13f79535-47bb-0310-9956-ffa450edef68