Restructure the find_route_worker() function. Basically,

it should take care of knowing about usable and unusable
workers. By centralizing this logic, it will make it
easier and more streamlined to add in the forthcoming
hot-standby status workers.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@420936 13f79535-47bb-0310-9956-ffa450edef68