[folks] Don't allow setting a Kf.Persona's alias to its current value

[Philip Withnall <pwithnall src gnome org>]

commit ae93e946acb356def0429ba36f1c71b72228930b
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Wed Sep 8 10:28:53 2010 +0100

    Don't allow setting a Kf.Persona's alias to its current value

 backends/key-file/kf-persona.vala |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/backends/key-file/kf-persona.vala b/backends/key-file/kf-persona.vala
index e41b355..fed5547 100644
--- a/backends/key-file/kf-persona.vala
+++ b/backends/key-file/kf-persona.vala
@@ -48,6 +48,9 @@ public class Folks.Backends.Kf.Persona : Folks.Persona,
 
       set
         {
+          if (this._alias == value)
+            return;
+
           this._alias = value;
           this.key_file.set_string (this.display_id, "__alias", value);