vbo: Eliminate short-circuiting in invalid-start case.

Now that we have a index_range_invalid flag, we can just use that rather
than calling vbo_validated_drawrangeelements directly and returning.

NOTE: This is a candidate for release branches.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>

src/mesa/vbo/vbo_exec_array.c

@@ -889,11 +889,7 @@ vbo_exec_DrawRangeElementsBaseVertex(GLenum mode,
                        start, end, basevertex, count, type, indices,
                        ctx->Array.ArrayObj->_MaxElement - 1);
       }
-
-      /* Just do an ordinary glDrawElementsBaseVertex(). */
-      vbo_validated_drawrangeelements(ctx, mode, GL_FALSE, 0, ~0,
-                                      count, type, indices, basevertex, 1);
-      return;
+      index_bounds_valid = GL_FALSE;
    }
 
    /* NOTE: It's important that 'end' is a reasonable value.