fix gcc warning: deleting object of polymorphic class type 'i2p::stream::StreamingDestination' which has non-virtual destructor might cause undefined behaviour [-Wdelete-non-virtual-dtor]

Identity.h

@@ -128,6 +128,7 @@ namespace data
 	{
 		public:
 
+			virtual ~LocalDestination() {};
 			virtual const IdentHash& GetIdentHash () const = 0;
 			virtual const uint8_t * GetEncryptionPrivateKey () const = 0; 
 			virtual const uint8_t * GetEncryptionPublicKey () const = 0;