Move process_child_status to mpm_common.c. This requires re-naming it

to ap_process_child_status and opening up ap_coredump_dir.  I have
modified all of the MPMs that I saw using this function to work with this
patch.  Sorry if I broke anybody.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@85808 13f79535-47bb-0310-9956-ffa450edef68