vote: allow block_id to be None until new shred format is rolled out

core/src/consensus.rs

@@ -592,10 +592,9 @@ impl Tower {
         // `self.vote_state`
         let block_id = bank.block_id().unwrap_or_else(|| {
             // This can only happen for our leader bank
-            assert!(
-                *bank.collector_id() == self.node_pubkey,
-                "block_id must not be None for a frozen non-leader bank"
-            );
+            // Note: since the new shred format is yet to be rolled out to all clusters,
+            // this can also happen for non-leader banks. Once rolled out we can assert
+            // here that this is our leader bank.
             Hash::default()
         });
         self.record_bank_vote_and_update_lockouts(

core/src/replay_stage.rs

@@ -3599,8 +3599,8 @@ impl ReplayStage {
             // Here we don't have to check if this is our leader bank, as since we are adopting this bank,
             // that means that it was created from a different instance (hot spare setup or a previous restart),
             // and thus we must have replayed and set the block_id from the shreds.
-            bank.block_id()
-                .expect("block_id for an adopted bank cannot be None")
+            // Note: since the new shred format is not rolled out everywhere, we have to provide a default
+            bank.block_id().unwrap_or_default()
         };
         tower.update_last_vote_from_vote_state(
             progress