node: fix clippy suggestion on borrowing — heartwood

Remove the borrow of rid to fix the clippy warning.

     let bob_inv = bob.storage().inventory().unwrap();
     let rid = bob_inv.first().unwrap();
     alice.seed(&rid, policy::Scope::Followed).unwrap();
     alice.seed(rid, policy::Scope::Followed).unwrap();
     alice.connect_to(&bob);
     // Alice receives Bob's refs.