Fix xml validation error
<name>DavLockDB</name>
<description>Location of the DAV lock database</description>
<syntax>DavLockDB <var>file-path</var></syntax>
+<default>DavLockDB DEFAULT_REL_STATEDIR/davlockdb</default>
<contextlist><context>server config</context><context>virtual host</context>
</contextlist>
-<default>DavLockDB <var>statedir</var>/davlockdb</default>
<compatibility>No default prior to version 2.5.1.</compatibility>
<usage>
