Merge r1668532, r1668535, r1668553 from trunk:

core: Initialize scoreboard's used optional functions on graceful restarts to
avoid a crash when relocation occurs.  PR 57177.


core: follow up to r1668532: CHANGES entry.

core: follow up to r1668532: always initialize optional_fn pointers in ap_create_scoreboard().
Submitted by: ylavic
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1670325 13f79535-47bb-0310-9956-ffa450edef68