Initialize the Evas_Native_Surface to 0 for dmabuf tests

ref e6f17dee5d

Should probably clear this one too, though the recent native surface api
changes won't cause any breakage here, future ones might.

src/bin/e_pixmap.c

@@ -1110,6 +1110,8 @@ e_pixmap_dmabuf_test(struct linux_dmabuf_buffer *dmabuf)
    int size;
    void *data;
 
+   memset(&ns, 0, sizeof(ns));
+
    if (e_comp->gl)
      {
         Eina_Bool ret;