changes to allow asset_source to be specified in the opensim.ini

this will work for sqlite and nhibernate, but will be ignored for
mysql and mssql (reverting to their ini files) until someone writes
that bit.

OpenSim/Data/AssetDataBase.cs

@@ -40,6 +40,7 @@ namespace OpenSim.Data
 
         public abstract string Version { get; }
         public abstract string Name { get; }
+        public abstract void Initialise(string connect);
         public abstract void Initialise();
     }
 }