[evolution] Check for m->cancel != NULL in mail_msg_cancel().

[Matthew Barnes <mbarnes src gnome org>]

commit bbb5b172dab0d9ba85cd48670ece04733b28c758
Author: Matthew Barnes <mbarnes redhat com>
Date:   Tue Sep 21 09:34:25 2010 -0400

    Check for m->cancel != NULL in mail_msg_cancel().

 mail/mail-mt.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/mail/mail-mt.c b/mail/mail-mt.c
index 595cedf..e17d3c2 100644
--- a/mail/mail-mt.c
+++ b/mail/mail-mt.c
@@ -303,7 +303,7 @@ void mail_msg_cancel (guint msgid)
 
 	m = g_hash_table_lookup (mail_msg_active_table, GINT_TO_POINTER (msgid));
 
-	if (m != NULL && !camel_operation_cancel_check (m->cancel))
+	if (m != NULL && m->cancel != NULL && !camel_operation_cancel_check (m->cancel))
 		camel_operation_cancel (m->cancel);
 
 	g_mutex_unlock (mail_msg_lock);