* mod_proxy: Allow setting options to globally defined balancer from

  ProxyPass used in VirtualHost. Balancers are now merged using the new
  merge_balancers method which merges the balancers options.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1667707 13f79535-47bb-0310-9956-ffa450edef68