[snappy] engine: don't try to save history if snappy has no content

[Luis de Bethencourt <luisbg src gnome org>]

commit a0ced4a18b4ea0a55ab2026703b7c23bec84e3bd
Author: Luis de Bethencourt <luis debethencourt com>
Date:   Tue Mar 26 13:19:45 2013 -0400

    engine: don't try to save history if snappy has no content

 src/gst_engine.c |    6 ++++--
 1 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/src/gst_engine.c b/src/gst_engine.c
index d8a5c44..4665d93 100644
--- a/src/gst_engine.c
+++ b/src/gst_engine.c
@@ -440,8 +440,10 @@ add_uri_unfinished (GstEngine * engine)
   gboolean ret;
   gint64 position;
 
-  position = query_position (engine);
-  ret = add_uri_unfinished_playback (engine, engine->uri, position);
+  if (engine->uri) {
+    position = query_position (engine);
+    ret = add_uri_unfinished_playback (engine, engine->uri, position);
+  }
 
   return ret;
 }