[evolution] Don't crash on missing EAlert definitions.

[Matthew Barnes <mbarnes src gnome org>]

commit 1347b66c5e8b51d1eb412688e14cb838a43db828
Author: Matthew Barnes <mbarnes redhat com>
Date:   Wed Apr 13 10:29:05 2011 -0400

    Don't crash on missing EAlert definitions.

 e-util/e-alert.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/e-util/e-alert.c b/e-util/e-alert.c
index 30afa8a..12a9256 100644
--- a/e-util/e-alert.c
+++ b/e-util/e-alert.c
@@ -553,6 +553,7 @@ alert_constructed (GObject *object)
 
 	alert = E_ALERT (object);
 	definition = alert->priv->definition;
+	g_return_if_fail (definition != NULL);
 
 	e_alert_set_message_type (alert, definition->message_type);
 	e_alert_set_default_response (alert, definition->default_response);