[smuxi/stable: 2/2] Engine: guard MessageBuilder.NormalizeNewlines()

[Mirco M. M. Bauer <mmmbauer src gnome org>]

commit 0baf630cae551d044fc11b37a70c2c4aaae0cbcd
Author: Mirco Bauer <meebey meebey net>
Date:   Tue Nov 3 18:22:19 2015 +0100

    Engine: guard MessageBuilder.NormalizeNewlines()
    
    If "text" only contains \n it will throw an ArgumentOutOfRangeException.

 src/Engine/Messages/MessageBuilder.cs |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/src/Engine/Messages/MessageBuilder.cs b/src/Engine/Messages/MessageBuilder.cs
index 7e6851d..6ff9713 100644
--- a/src/Engine/Messages/MessageBuilder.cs
+++ b/src/Engine/Messages/MessageBuilder.cs
@@ -807,7 +807,9 @@ namespace Smuxi.Engine
                 normalized.AppendFormat("{0} ", trimmed);
             }
             // remove trailing space
-            normalized.Length--;
+            if (normalized.Length > 0) {
+                normalized.Length--;
+            }
             return normalized.ToString();
         }