[Mono.Security]: 'Mono.Security.Interface.MonoSslStream' needs to implement IDisposable.

(cherry picked from commit 4c1760785a60b01f0be41b312c791fae23699ba4)

mcs/class/Mono.Security/Mono.Security.Interface/MonoSslStream.cs

@@ -36,7 +36,7 @@ using Mono.Net.Security;
 
 namespace Mono.Security.Interface
 {
-	public abstract class MonoSslStream
+	public abstract class MonoSslStream : IDisposable
 	{
 		public abstract void AuthenticateAsClient (string targetHost);