[evolution-data-server] Fix runtime warning in camel_filter_driver_flush().

[Matthew Barnes <mbarnes src gnome org>]

commit 6d3b9dcbe6ddde71699dd9a29c9de6bc06c62b65
Author: Matthew Barnes <mbarnes redhat com>
Date:   Mon Jul 12 07:49:58 2010 -0400

    Fix runtime warning in camel_filter_driver_flush().
    
    Only propagate the error if there's an error to propagate.

 camel/camel-filter-driver.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/camel/camel-filter-driver.c b/camel/camel-filter-driver.c
index b52a561..528b83d 100644
--- a/camel/camel-filter-driver.c
+++ b/camel/camel-filter-driver.c
@@ -1179,7 +1179,8 @@ camel_filter_driver_flush (CamelFilterDriver *driver,
 
 	g_hash_table_foreach_remove (p->only_once, (GHRFunc) run_only_once, &data);
 
-	g_propagate_error (error, data.error);
+	if (data.error != NULL)
+		g_propagate_error (error, data.error);
 }
 
 static gint