malloc + memset -> zalloc

And for clients using the xmalloc helper, use xzalloc.

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
diff --git a/src/data-device.c b/src/data-device.c
index a76ae16..46081d4 100644
--- a/src/data-device.c
+++ b/src/data-device.c
@@ -382,13 +382,12 @@
 		return;
 	}
 
-	drag = malloc(sizeof *drag);
+	drag = zalloc(sizeof *drag);
 	if (drag == NULL) {
 		wl_resource_post_no_memory(resource);
 		return;
 	}
 
-	memset(drag, 0, sizeof *drag);
 	drag->grab.interface = &drag_grab_interface;
 	drag->client = client;