Backport from trunk and 2.2.x:

  mod_ldap: Brad's pool fixes to fix a race condition during
  first request as well as thread-safety issues between threads
  handling different vhosts at steady state

Submitted by: bnicholes
Reviewed by:  trawick, gregames



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.0.x@393264 13f79535-47bb-0310-9956-ffa450edef68