compositor: fix event-test

event-test assumes, that even without the very first wl_surface.attach
(and commit), the surface will have infinite (previously undef) input
region. event-test simply has test-client to create a wl_surface, and
then it forcefully sets its position and size, and assumes the input
region is now the full surface, so that notify_motion() will hit it.

Change Weston to initialize the input region to infinite, instead of
empty.

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/src/compositor.c b/src/compositor.c
index 4dd6d27..f4c933e 100644
--- a/src/compositor.c
+++ b/src/compositor.c
@@ -247,7 +247,7 @@
 	pixman_region32_init(&surface->damage);
 	pixman_region32_init(&surface->opaque);
 	pixman_region32_init(&surface->clip);
-	pixman_region32_init(&surface->input);
+	region_init_infinite(&surface->input);
 	pixman_region32_init(&surface->transform.opaque);
 	wl_list_init(&surface->frame_callback_list);