Change the Windows MPM to only use the pre_mpm phase in the parent process.

Change the Windows MPM to only use the pre_mpm phase in the parent process.
The child processes use the child_init phase to reattach to the shared
memory.  This makes Windows work like Unix, which should make it easier
for module authors to write portable modules.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93119 13f79535-47bb-0310-9956-ffa450edef68