[PATCH] register shutdown actions for apache child die

apache2handler sapi registers cleanup functions only for main apache process.
But apache 2 cleans only child pool before it die.
This is reason for unclean connection closes in persistent connection (in pgsql exactly).

This patch adds shutdown actions registration on each child init.
Apache child will be call php_apache_server_shutdow() before it die like handler for Apache 1.3.
This patch closes bug #39330.