Doc Webdav: fix bug with DAV propname namespaces

Since the self.PROPS hadn't been copied, subsequent propname requests
would try to fetch all the properties of previous ones.

bzr revid: p_christ@hol.gr-20100729133937-yyfm1wb33vxh96ew

addons/document_webdav/dav_fs.py

@@ -79,6 +79,7 @@ class openerp_dav_handler(dav_interface):
             return props
         node = self.uri2object(cr, uid, pool, uri2)
         if node:
+            props = props.copy()
             props.update(node.get_dav_props(cr))
         cr.close()     
         return props