patch 8.1.0864: cannot have a local value for 'scrolloff' and 'sidescrolloff'

Problem:    Cannot have a local value for 'scrolloff' and 'sidescrolloff'.
            (Gary Holloway)
Solution:   Make 'scrolloff' and 'sidescrolloff' global-local. (mostly by
            Aron Widforss, closes #3539)
diff --git a/src/ex_docmd.c b/src/ex_docmd.c
index 1646a22..b90ea7b 100644
--- a/src/ex_docmd.c
+++ b/src/ex_docmd.c
@@ -8923,7 +8923,7 @@
 	{
 	    if (wp->w_p_scb && wp->w_buffer)
 	    {
-		y = wp->w_buffer->b_ml.ml_line_count - p_so;
+		y = wp->w_buffer->b_ml.ml_line_count - get_scrolloff_value();
 		if (topline > y)
 		    topline = y;
 	    }