demo: Prevent double-free in Gtk demo
demo: Prevent double-free in Gtk demo

In keeping with the recent buxton wire API change that ensures all resources
are free'd upon closing a connection, the demo now ensures that we only
cleanup our BuxtonClient if its successfully connected within its lifetime.

Signed-off-by: Michael Ikey Doherty <15e2f59c60e9d84348e78a87e24660774f739add@intel.com>

sofar/buxton,sofar/buxton