[gnome-builder/wip/greeter] egg-signal-group: add more assertions

[Christian Hergert <chergert src gnome org>]

commit 9338f92bfdc36dc15fb5f56485bb24d6972a3722
Author: Christian Hergert <christian hergert me>
Date:   Sun May 10 23:59:56 2015 -0700

    egg-signal-group: add more assertions
    
    If there's something strange, in your backtraces. Who you gonna call.
    g assert.

 contrib/egg/egg-signal-group.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/contrib/egg/egg-signal-group.c b/contrib/egg/egg-signal-group.c
index 70042d1..dc70e8a 100644
--- a/contrib/egg/egg-signal-group.c
+++ b/contrib/egg/egg-signal-group.c
@@ -132,6 +132,8 @@ egg_signal_group_bind_handler (EggSignalGroup *self,
                                                    handler->closure,
                                                    handler->connect_after);
 
+  g_assert (handler->handler_id != 0);
+
   for (i = 0; i < self->block_count; i++)
     g_signal_handler_block (self->target, handler->handler_id);
 }