Obsolete unused old version type methods

SByteType seems to have implemented IVersionType previously, but that is
no more the case.

Author: fredericDelaporte

src/NHibernate/Type/SByteType.cs

@@ -73,16 +73,22 @@ public override object FromStringValue(string xml)
 
 		#region IVersionType Members
 
+		// Since 5.2
+		[Obsolete("This member has no more usage and will be removed in a future version.")]
 		public virtual object Next(object current, ISessionImplementor session)
 		{
 			return (SByte)((SByte)current + 1);
 		}
 
+		// Since 5.2
+		[Obsolete("This member has no more usage and will be removed in a future version.")]
 		public virtual object Seed(ISessionImplementor session)
 		{
 			return (SByte)1;
 		}
 
+		// Since 5.2
+		[Obsolete("This member has no more usage and will be removed in a future version.")]
 		public IComparer Comparator
 		{
 			get { return Comparer<SByte>.Default; }
@@ -105,4 +111,4 @@ public override string ObjectToSQLString(object value, Dialect.Dialect dialect)
 			return value.ToString();
 		}
 	}
-}
+}