Cleanup unused proofCount

Summary:
Early exit by tracking proofCount became unworkable in D14663

It is now no longer used.

Test Plan:
  ninja check && ninja check-functional

Reviewers: O1 Bitcoin ABC, #bitcoin_abc, Fabien

Reviewed By: O1 Bitcoin ABC, #bitcoin_abc, Fabien

Differential Revision: https://reviews.bitcoinabc.org/D16410

src/net_processing.cpp

@@ -6505,7 +6505,6 @@ void PeerManagerImpl::ProcessMessage(
  return;
  }
 
- size_t proofCount = 0;
  std::vector<std::pair<avalanche::ProofId, bool>> remoteProofsStatus;
  m_avalanche->withPeerManager([&](const avalanche::PeerManager &pm) {
  pm.forEachPeer([&](const avalanche::Peer &peer) {
@@ -6524,8 +6523,6 @@ void PeerManagerImpl::ProcessMessage(
  added > 0);
  }
 
- proofCount += added;
-
  // In order to properly determine which proof is missing, we
  // need to keep scanning for all our proofs.
  return true;