mpm_winnt: Factor out a helper function to parse the type of an accept

filter and use an appropriate enum for it.

This makes the code in winnt_accept() a bit easier to follow.  As a minor
side effect, it also fixes a small bug where the "unrecognized AcceptFilter
'%s'" log entry would always contain "none" instead of the actually
unrecognized kind of the accept filter.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1801144 13f79535-47bb-0310-9956-ffa450edef68