don't count workers in processes which aren't actively serving requests.

it is necessary to check for the generation as well as "quiescing", in the
case of a restart where no workers have seen the PoD yet.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@89821 13f79535-47bb-0310-9956-ffa450edef68