[gnome-todo] task: don't return NULL title

[Georges Basile Stavracas Neto <gbsneto src gnome org>]

commit f3ac87ab86f0774465887c2bdc2f0c4e6391c439
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Sat Jun 27 11:36:28 2015 -0300

    task: don't return NULL title

 src/gtd-task.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/gtd-task.c b/src/gtd-task.c
index 8bbd0fc..58d2c5a 100644
--- a/src/gtd-task.c
+++ b/src/gtd-task.c
@@ -770,7 +770,7 @@ gtd_task_get_title (GtdTask *task)
 
   e_cal_component_get_summary (task->priv->component, &summary);
 
-  return summary.value;
+  return summary.value ? summary.value : "";
 }
 
 /**