[gnumeric] SheetView: fix typo causing crashes on sheet object removal.

[Morten Welinder <mortenw src gnome org>]

commit 905a9cce69535bcd7ab8d95cfb16ba6ef94f8fd0
Author: Morten Welinder <terra gnome org>
Date:   Tue Oct 2 20:51:41 2018 -0400

    SheetView: fix typo causing crashes on sheet object removal.

 ChangeLog        | 4 ++++
 src/sheet-view.c | 2 +-
 2 files changed, 5 insertions(+), 1 deletion(-)
---
diff --git a/ChangeLog b/ChangeLog
index 7dfa75cdd..7acc3c5f5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2018-10-02  Morten Welinder  <terra gnome org>
+
+       * src/sheet-view.c (sv_real_dispose): Fix typo.
+
 2018-10-01  Morten Welinder  <terra gnome org>
 
        * src/workbook-view.c (wb_view_set_property): Fix setting of
diff --git a/src/sheet-view.c b/src/sheet-view.c
index e4d3cd7ab..d543765d6 100644
--- a/src/sheet-view.c
+++ b/src/sheet-view.c
@@ -223,7 +223,7 @@ sv_real_dispose (GObject *object)
        while (sv->controls->len > 0) {
                SheetControl *control =
                        g_ptr_array_index (sv->controls,
-                                          sv->controls->len - 10);
+                                          sv->controls->len - 1);
                gnm_sheet_view_detach_control (sv, control);
                g_object_unref (control);
        }