Merge r1777923 from trunk:

avoid SO_REUSEPORT w/o ListenCoresBucketsRatio 

Can lead to unintended/confusing sharing between 
multiple servers started by the same ID.

Submitted by: covener
Reviewed by: jorton, covener, wrowe


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1787301 13f79535-47bb-0310-9956-ffa450edef68