[libchamplain] Add missing return

[Pierre-Luc Beaudoin <plbeaudoin src gnome org>]

commit 0e7eee8c9316ad2a6bcc2369f1e98333886c49fd
Author: Simon Wenner <simon wenner ch>
Date:   Thu Sep 10 19:28:35 2009 +0200

    Add missing return

 champlain/champlain-map-data-source.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/champlain/champlain-map-data-source.c b/champlain/champlain-map-data-source.c
index a980873..046a43c 100644
--- a/champlain/champlain-map-data-source.c
+++ b/champlain/champlain-map-data-source.c
@@ -125,6 +125,7 @@ static MemphisMap*
 champlain_map_data_source_real_get_map_data (ChamplainMapDataSource *self)
 {
   g_error ("Should not be reached");
+  return NULL;
 }
 
 static void