Add apr_sockaddr_info_copy(), for making a deep copy of an
apr_sockaddr_t into a specified pool.

Submitted by: Yann Ylavic <ylavic.dev gmail.com>
Reviewed by: trawick


git-svn-id: https://svn.apache.org/repos/asf/apr/apr/trunk@1587045 13f79535-47bb-0310-9956-ffa450edef68