Retain signal handling in the worker MPM for the one_process case

(httpd with -DDEBUG, -X, or -DONE_PROCESS).

Fix -X, -DNO_DETACH, -DONE_PROCESS, etc. flags.

Tested on solaris w/ start/stop, restart, graceful, and with the
above debugging flags.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@93403 13f79535-47bb-0310-9956-ffa450edef68