Fix CDS LastChange parser updateID handling
Fix CDS LastChange parser updateID handling

The CDS LastChange parser is currently always returning 0 for the
updateID of a last change event.  This is because it is trying to
extract the value from a child node rather than an attribute.  This
commit fixes the problem by treating the updateID as an attribute.

https://bugzilla.gnome.org/show_bug.cgi?id=689808

GNOME/gupnp-av