Enable ProxySet inside <Proxy> section to

create balancer or worker if they were not
already created.
This allows to have ProxySet directive before
BalancerMember directives inside Proxy section.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@427920 13f79535-47bb-0310-9956-ffa450edef68