xenstore: fix add_change_node()

xenstore: fix add_change_node()

add_change_node() in xenstored is used to add a modified node to the
list of changed nodes of one transaction. It is being called with the
recurse parameter set to true when removing a node in order to get
watches for children of the node fired at transaction end, too.

If, however, the node to be deleted had been modified in the same
transaction the recurse parameter of add_change_node() is lost as
an entry already in the list of the changed nodes won't be entered
again.

Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>