egl/dri2: don't leak the fd on dri2_terminate

Currently the check was incorrect as it did not consider the (unlikely)
case of fd == 0. In order to fix this we should first correctly
initialize it to -1, as the swrast implementations leave it set to zero
(props to calloc()).

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Boyan Ding <boyan.j.ding@gmail.com>
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index eb56113..1740ee3 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -786,7 +786,7 @@
 
    if (dri2_dpy->own_dri_screen)
       dri2_dpy->core->destroyScreen(dri2_dpy->dri_screen);
-   if (dri2_dpy->fd)
+   if (dri2_dpy->fd >= 0)
       close(dri2_dpy->fd);
    if (dri2_dpy->driver)
       dlclose(dri2_dpy->driver);