[f-spot] Avoid exception when thumbnailed file is missing.

[Ruben Vermeersch <rubenv src gnome org>]

commit a8001d1288b7cb2f87f60d7f32a39064c7e7a48e
Author: Ruben Vermeersch <ruben savanne be>
Date:   Mon Jun 14 23:25:30 2010 +0200

    Avoid exception when thumbnailed file is missing.

 src/Utils/XdgThumbnailSpec.cs |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/Utils/XdgThumbnailSpec.cs b/src/Utils/XdgThumbnailSpec.cs
index c9eabf9..1d0850f 100644
--- a/src/Utils/XdgThumbnailSpec.cs
+++ b/src/Utils/XdgThumbnailSpec.cs
@@ -111,6 +111,9 @@ namespace FSpot.Utils
             }
 
             var file = GLib.FileFactory.NewForUri (uri);
+            if (!file.Exists)
+                return false;
+
             var info = file.QueryInfo ("time::modified", GLib.FileQueryInfoFlags.None, null);
 
             if (pixbuf.GetOption (ThumbMTimeOpt) != info.GetAttributeULong ("time::modified").ToString ()) {