Narrow a parameter in apply_encrypted_vote_tally

The signature proof is verified by the caller, it's misleading to have
it passed into the method only to use the id.

chain-impl-mockchain/src/ledger/ledger.rs

@@ -1159,7 +1159,7 @@ impl Ledger {
 
         self.votes = self
             .votes
-            .apply_encrypted_vote_tally(self.date(), &stake, tally, sig)?;
+            .apply_encrypted_vote_tally(self.date(), &stake, tally, sig.id)?;
 
         Ok(self)
     }

chain-impl-mockchain/src/vote/ledger.rs

@@ -1,4 +1,4 @@
-use crate::certificate::{EncryptedVoteTally, EncryptedVoteTallyProof};
+use crate::certificate::EncryptedVoteTally;
 use crate::{
     certificate::{TallyProof, VoteAction, VoteCast, VotePlan, VotePlanId, VoteTally},
     date::BlockDate,
@@ -185,12 +185,13 @@ impl VotePlanLedger {
         block_date: BlockDate,
         stake: &StakeControl,
         encrypted_tally: &EncryptedVoteTally,
-        sig: EncryptedVoteTallyProof,
+        committee_id: CommitteeId,
     ) -> Result<Self, VotePlanLedgerError> {
         let id = encrypted_tally.id().clone();
 
         let r = self.plans.update(&id, move |v| {
-            v.start_private_tally(block_date, stake, sig.id).map(Some)
+            v.start_private_tally(block_date, stake, committee_id)
+                .map(Some)
         });
 
         match r {