Remove empty twin_path_bevel_shape

Remove the empty and unused static routine twin_path_bevel_shape().
Fixes unused parameter build warnings.

Signed-off-by: Geoff Levand <geoff@infradead.org>

libtwin/twin_widget.c

diff --git a/libtwin/twin_widget.c b/libtwin/twin_widget.c
index 30b3ae0..3906de3 100644
--- a/libtwin/twin_widget.c
+++ b/libtwin/twin_widget.c
@@ -188,19 +188,6 @@
 	    0 <= y && y < _twin_widget_height(widget)); 
 }
 
-static twin_path_t *
-_twin_path_bevel_shape (twin_shape_t	shape,
-			twin_bool_t	upper,
-			twin_coord_t	left,
-			twin_coord_t	top,
-			twin_coord_t	right,
-			twin_coord_t	bottom,
-			twin_fixed_t	radius,
-			twin_fixed_t	bw)
-{
-    return 0;
-}
-
 void
 _twin_widget_bevel (twin_widget_t   *widget,
 		    twin_fixed_t    b,