Merge r1639614 from trunk:

don't call notify_suspend() in a worker thread after 
start_lingering_close_common may have put the socket back
into the pollset. 

If it becomes readable too quickly, cs can be
free'ed or accessed concurrently.

Submitted by: covener
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1642858 13f79535-47bb-0310-9956-ffa450edef68