[gnumeric] Compilation: warning fixes.

[Morten Welinder <mortenw src gnome org>]

commit 3c84bb38218dee2a9a6df6efa0998fe3c13e26d7
Author: Morten Welinder <terra gnome org>
Date:   Tue Sep 27 19:49:14 2016 -0400

    Compilation: warning fixes.

 src/colrow.h   |    3 ++-
 src/commands.c |    6 ++++--
 2 files changed, 6 insertions(+), 3 deletions(-)
---
diff --git a/src/colrow.h b/src/colrow.h
index 1cedcb3..9e4bf57 100644
--- a/src/colrow.h
+++ b/src/colrow.h
@@ -134,7 +134,8 @@ void                 colrow_set_visibility          (Sheet *sheet, gboolean is_cols,
                                                 gboolean visible, int first, int last);
 void            colrow_get_global_outline      (Sheet const *sheet, gboolean is_cols, int depth,
                                                 ColRowVisList  **show, ColRowVisList   **hide);
-#define colrow_vis_list_destroy(l) (g_slist_free_full ((l), g_free), NULL)
+
+#define colrow_vis_list_destroy(l) g_slist_free_full ((l), g_free)
 gint             colrow_vis_list_length         (ColRowVisList *list);
 void            colrow_set_visibility_list     (Sheet *sheet, gboolean is_cols,
                                                 gboolean visible,
diff --git a/src/commands.c b/src/commands.c
index 23a960b..742f85a 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -2305,8 +2305,10 @@ static void
 cmd_colrow_hide_finalize (GObject *cmd)
 {
        CmdColRowHide *me = CMD_COLROW_HIDE (cmd);
-       me->hide = colrow_vis_list_destroy (me->hide);
-       me->show = colrow_vis_list_destroy (me->show);
+       colrow_vis_list_destroy (me->hide);
+       me->hide = NULL;
+       colrow_vis_list_destroy (me->show);
+       me->show = NULL;
        gnm_command_finalize (cmd);
 }