Fix a bug in r1604350 that can lead to crashes in the event MPM under load.

if start_lingering_close_blocking() returns 0, notify_suspend() will 
write a 1 into some potentially recently free'd memory from 
ptrans (cs->suspended).


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1638691 13f79535-47bb-0310-9956-ffa450edef68