evdev: Discard events from a touchscreen paired with an unplugged output

Commit 17bccaed intended to make the events coming from a touchscreen
paired with an unplugged output to be discarded, while an unpaired one
would just choose a different output. However, the logic was inverted
causing the opposite to happen.

Later in commit 161c6c56, the default behavior was changed to map an
output to a default output if the one specified via udev is not
present. This change is reverted by this patch.

v2: undo the change from commit 161c6c56.

v3: deal with libinput too.

src/evdev.c

@@ -602,7 +602,7 @@ notify_output_destroy(struct wl_listener *listener, void *data)
 	struct weston_compositor *c = device->seat->compositor;
 	struct weston_output *output;
 
-	if (device->output_name) {
+	if (!device->output_name) {
 		output = container_of(c->output_list.next,
 				      struct weston_output, link);
 		evdev_device_set_output(device, output);

src/libinput-device.c

@@ -264,7 +264,7 @@ notify_output_destroy(struct wl_listener *listener, void *data)
 	struct weston_compositor *c = device->seat->compositor;
 	struct weston_output *output;
 
-	if (device->output_name) {
+	if (!device->output_name) {
 		output = container_of(c->output_list.next,
 				      struct weston_output, link);
 		evdev_device_set_output(device, output);

src/libinput-seat.c

@@ -84,9 +84,7 @@ device_added(struct udev_input *input, struct libinput_device *libinput_device)
 		wl_list_for_each(output, &c->output_list, link)
 			if (strcmp(output->name, device->output_name) == 0)
 				evdev_device_set_output(device, output);
-	}
-
-	if (device->output == NULL) {
+	} else if (device->output == NULL) {
 		output = container_of(c->output_list.next,
 				      struct weston_output, link);
 		evdev_device_set_output(device, output);

src/udev-seat.c

@@ -125,9 +125,7 @@ device_added(struct udev_device *udev_device, struct udev_input *input)
 		wl_list_for_each(output, &c->output_list, link)
 			if (strcmp(output->name, device->output_name) == 0)
 				evdev_device_set_output(device, output);
-	}
-
-	if (device->output == NULL) {
+	} else if (device->output == NULL) {
 		output = container_of(c->output_list.next,
 				      struct weston_output, link);
 		evdev_device_set_output(device, output);