Fix hangs reading xml

[xyzzy42]

webdavd will hang in an infinite loop on startup for various simple mistakes in the xml.

Anything malformed, like missing a closing tag for an element.

<server> <listen> <listen-without-slash> </server>
<server> <listen> /listen> </server>

Any unknown element in a listen: <listen> <typo> 1234 </typo> </listen>

Unknown elements in a server were handled.

[couling]

Great Find! Thanks.