Remove the thread mutex from the worker... it really should be

in the balancer. Thus we have global and thread for the balancer.
Use global when updating the full, shm list of workers; use
thread when being local.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1068581 13f79535-47bb-0310-9956-ffa450edef68