fix "long lost child came home!" messages after a graceful restart with

MaxClients (== ap_daemons_limit) lowered.  This leaves junk at the end of
the formerly used part of the scoreboard.  If you then decide to raise
MaxClients via graceful, the junk prevents those scoreboard slots from
being used.

This should not impact performance because find_child_by_pid stops its
search when it sees a matching pid.  If we don't have a match, something
else is busted.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@97287 13f79535-47bb-0310-9956-ffa450edef68