Add missing quote in action response
Add missing quote in action response

The action response document was missing an opening quote
sign in the namespace declaration of the <actionResponse>
element.

Fix it by adding the missing quote and also tweak the code
a bit to output well-formed XML in case that the service-type
is not set.

GNOME/gupnp,GNOME/gupnp,GNOME/gupnp,GNOME/gupnp