For apr-util-1.3 seperate ldap link options, and default to old behavoir

when linking against apr-util-1.2.

Backports: 663663
Reviewed by: rpluem, fielding, minfrin, 


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@665732 13f79535-47bb-0310-9956-ffa450edef68