[gcalctool/vala] Fix error in serializer

[Robert Ancell <rancell src gnome org>]

commit d30a850ffa0f5eeadee63219cdaf53648b672641
Author: Robert Ancell <robert ancell canonical com>
Date:   Sat Oct 13 09:33:06 2012 +1300

    Fix error in serializer

 src/serializer.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/src/serializer.vala b/src/serializer.vala
index 53e16ab..d24e957 100644
--- a/src/serializer.vala
+++ b/src/serializer.vala
@@ -421,7 +421,7 @@ public class Serializer : Object
             append_exponent (string, exponent);
         }
 
-        return string.str.substring (0, string.len + 1);
+        return string.str;
     }
 
     private void append_exponent (StringBuilder string, int exponent)