Handle Microsoft expectation for a 404 with PROPFIND

[dgraziotin]

This is part of #8.

Using the "Map Network Drive" feature.

When adding the WebDAV location (e.g., http://192.168.178.99:32080), Windows/Explorer would fail to connect and give an error.

At this point, a PROPFIND request is issued when setting up the connection.

The issue is that Microsoft as well as IIS, expects an HTTP 404 in the response headers, whereas RFC2518 recommends an HTTP 207 with the error descriptions in the response body (an XML file).

Somebody (Russian, use Google Translate) proposed as fix to create an ad-hoc response for Microsoft only that would return 404. Implementing this solution restores access to the WebDAV location.