[gnome-builder] ls: be resillient against NULL date times

[Christian Hergert <chergert src gnome org>]

commit 83418f5063aeee08d6454a7bd8af3c7cc07f0bd4
Author: Christian Hergert <chergert redhat com>
Date:   Wed Sep 4 13:31:36 2019 -0700

    ls: be resillient against NULL date times

 src/plugins/ls/gbp-ls-page.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
diff --git a/src/plugins/ls/gbp-ls-page.c b/src/plugins/ls/gbp-ls-page.c
index 111b98334..a438eea6a 100644
--- a/src/plugins/ls/gbp-ls-page.c
+++ b/src/plugins/ls/gbp-ls-page.c
@@ -111,7 +111,10 @@ modified_cell_data_func (GtkCellLayout   *cell_layout,
   gtk_tree_model_get (tree_model, iter,
                       GBP_LS_MODEL_COLUMN_MODIFIED, &when,
                       -1);
-  format = dzl_g_date_time_format_for_display (when);
+
+  if (when != NULL)
+    format = dzl_g_date_time_format_for_display (when);
+
   g_object_set (cell, "text", format, NULL);
 }