[smuxi] Engine: use correct version value in Engine.VersionString

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

commit d03e9334ed863b71fe2e13d52405be9e18b2c89c
Author: Mirco Bauer <meebey meebey net>
Date:   Sat May 2 13:17:11 2015 +0200

    Engine: use correct version value in Engine.VersionString
    
    _Version was never initialized since the refactoring of
    e11d17d57cced079a4d82eb794a2ecb4e83421a8

 src/Engine/Engine.cs |    4 +---
 1 files changed, 1 insertions(+), 3 deletions(-)
---
diff --git a/src/Engine/Engine.cs b/src/Engine/Engine.cs
index 5c29ef7..9549db2 100644
--- a/src/Engine/Engine.cs
+++ b/src/Engine/Engine.cs
@@ -31,8 +31,6 @@ namespace Smuxi.Engine
     public class Engine
     {
         private static bool             _IsInitialized;
-        private static Version          _Version;
-        private static string           _VersionNumber;
         private static string           _VersionString;
         private static Config           _Config;
         private static SessionManager   _SessionManager;
@@ -106,7 +104,7 @@ namespace Smuxi.Engine
             _VersionString = String.Format(
                 "{0} {1}{2} - running on {3} {4}",
                 Path.GetFileNameWithoutExtension(asm_name.Name),
-                _Version,
+                AssemblyVersion,
                 distVersion,
                 Platform.OperatingSystem,
                 Platform.Architecture