[folks] Fix the calculation for the persona_store_id length in Persona.split_uid().

[Travis Reitter <treitter src gnome org>]

commit 7aa66a278818094e82cd8b108ab30cba6ef9d480
Author: Travis Reitter <travis reitter collabora co uk>
Date:   Mon Aug 23 13:07:30 2010 -0700

    Fix the calculation for the persona_store_id length in Persona.split_uid().

 folks/persona.vala |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/folks/persona.vala b/folks/persona.vala
index fb3127f..5a5d0a8 100644
--- a/folks/persona.vala
+++ b/folks/persona.vala
@@ -200,7 +200,8 @@ public abstract class Folks.Persona : Object
               if (backend_name_length == 0)
                 backend_name_length = ((char*) i) - ((char*) uid);
               else
-                persona_store_id_length = ((char*) i) - ((char*) uid);
+                persona_store_id_length =
+                  (((char*) i) - ((char*) uid)) - backend_name_length - 1;
             }
         }