removes seed and slot fields from Packet.Meta

507367e6ac
updated window-service to send shreds (as opposed to packets) to
retransmit-stage and so seed and slot fields in Packet.Meta are unused:
https://github.com/solana-labs/solana/blob/d6ec103be/sdk/src/packet.rs#L27-L28

sdk/src/packet.rs

@@ -1,5 +1,4 @@
 use {
-    crate::clock::Slot,
     bincode::Result,
     serde::Serialize,
     std::{
@@ -24,8 +23,6 @@ pub struct Meta {
     pub addr: [u16; 8],
     pub port: u16,
     pub v6: bool,
-    pub seed: [u8; 32],
-    pub slot: Slot,
     pub is_tracer_tx: bool,
     pub is_simple_vote_tx: bool,
 }