Add a Listen directive to the default config file. This allows us to

Add a Listen directive to the default config file.  This allows us to
later add another listen directive, in the default SSL config file,
without stopping the server from listening on port 80.  The next step
is to combine the Port and ServerName directives, so that Port can go
away finally.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@91260 13f79535-47bb-0310-9956-ffa450edef68