Remove unnecessary friend declaration

Author: gumb0

libp2p/Peer.h

@@ -54,8 +54,6 @@ class Peer: public Node
 	friend class Session;		/// Allows Session to update score and rating.
 	friend class Host;		/// For Host: saveNetwork(), restoreNetwork()
 
-	friend class RLPXHandshake;
-
 public:
 	/// Construct Peer from Node.
 	Peer(Node const& _node): Node(_node) {}