[f-spot] Fix cast to be less error-prone.

[Ruben Vermeersch <rubenv src gnome org>]

commit bba348ae7977d81c9caf72d87f02902eb8de4c9f
Author: Ruben Vermeersch <ruben savanne be>
Date:   Fri Jun 11 22:22:59 2010 +0200

    Fix cast to be less error-prone.

 src/UI.Dialog/ImportDialog.cs |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/UI.Dialog/ImportDialog.cs b/src/UI.Dialog/ImportDialog.cs
index 056dff3..cdc79f4 100644
--- a/src/UI.Dialog/ImportDialog.cs
+++ b/src/UI.Dialog/ImportDialog.cs
@@ -101,7 +101,7 @@ namespace FSpot.UI.Dialog
             // Populates the source combo box
             Sources = new TreeStore (typeof(ImportSource), typeof(string), typeof(string), typeof(bool));
             sources_combo.Model = Sources;
-            sources_combo.RowSeparatorFunc = (m, i) => ((string) m.GetValue (i, 1)) == String.Empty;
+            sources_combo.RowSeparatorFunc = (m, i) => (m.GetValue (i, 1) as string) == String.Empty;
             var render = new CellRendererPixbuf ();
             sources_combo.PackStart (render, false);
             sources_combo.SetAttributes (render, "icon-name", 2, "sensitive", 3);