[pan2] fix segfault in task-pane.cc:148

[Heinrich MÃller <henmull src gnome org>]

commit 4ad897193ca1471423cab6b21abb859b49232bbf
Author: Heinrich MÃller <henmull src gnome org>
Date:   Sun Dec 9 21:14:02 2012 +0100

    fix segfault in task-pane.cc:148

 pan/gui/task-pane.cc |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/pan/gui/task-pane.cc b/pan/gui/task-pane.cc
index d30fa15..a8b91b8 100644
--- a/pan/gui/task-pane.cc
+++ b/pan/gui/task-pane.cc
@@ -145,6 +145,8 @@ namespace
 void
 TaskPane :: show_task_info(const tasks_t& tasks)
 {
+  
+  if (tasks.size() == 0) return;  
   Task* task (tasks.front());
   if (!task) return;