Allow optional name=value options within <Proxy

section line. Additional arguments are allowed
only for 'standard' url's, meaning that the wildchar
urls will return error like before.
This allow to specify the worker/balancer parameters
on the definition line, without the need for extra
ProxySet options.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@427928 13f79535-47bb-0310-9956-ffa450edef68