Retract veto over inconsistent behaviour between directory and file wildcards,

implement wrowe's missing directory wilcard must fail / missing file wildcard
must pass requirement. Introduce 'optional' and 'strict' modifiers to the
Include directive for the end user to express their desired behaviour.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@929318 13f79535-47bb-0310-9956-ffa450edef68