Clarify when CoreDumpDirectory can be moot based on OS configuration, and

mention SIGQUIT/3 not being processed by the signal handler.  

SIGQUIT may unfortunately be a go-to signal for java users.



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@759957 13f79535-47bb-0310-9956-ffa450edef68