[banshee] Audiobook: fix MissingIntPtrCtorException

[AndrÃs Aragoneses <aaragoneses src gnome org>]

commit a966a17aed94b11b4b1b117daf1d285208758c20
Author: Andres G. Aragoneses <knocte gmail com>
Date:   Fri Oct 21 15:32:46 2011 +0100

    Audiobook: fix MissingIntPtrCtorException
    
    Another protected ctor addition. This should fix
    bgo#642833

 .../Banshee.Audiobook/AudiobookGrid.cs             |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/Extensions/Banshee.Audiobook/Banshee.Audiobook/AudiobookGrid.cs b/src/Extensions/Banshee.Audiobook/Banshee.Audiobook/AudiobookGrid.cs
index 46d1a35..440e5f2 100644
--- a/src/Extensions/Banshee.Audiobook/Banshee.Audiobook/AudiobookGrid.cs
+++ b/src/Extensions/Banshee.Audiobook/Banshee.Audiobook/AudiobookGrid.cs
@@ -66,6 +66,10 @@ namespace Banshee.Audiobook
             RowActivated += (o, a) => library.Actions["AudiobookOpen"].Activate ();
         }
 
+        protected AudiobookGrid (IntPtr raw) : base ()
+        {
+        }
+
         public void SetLibrary (AudiobookLibrarySource library)
         {
             SetModel (library.BooksModel);