grilo-test-ui: Fix crash if app couldn't get on the bus
grilo-test-ui: Fix crash if app couldn't get on the bus

If the application couldn't own a name on the session bus, then it would
never setup its UI, and view would be a NULL pointer which we'd
dereference, and crash.

Exit early from cleanup function if the view was never setup.

GNOME/grilo,GNOME/grilo