Comment the mpm_winnt backport proposal that is hanging

around for quite some time. In essence it allows the clean
shutdown of httpd when MaxClients is higher then 257


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@557931 13f79535-47bb-0310-9956-ffa450edef68