GH-2057 Remove unneeded hs_dpos_irreversible_blocknum

libraries/chain/include/eosio/chain/block_header_state_legacy.hpp

@@ -28,10 +28,6 @@ using signer_callback_type = std::function<std::vector<signature_type>(const dig
 
 struct block_header_state_legacy;
 
-// totem for dpos_irreversible_blocknum after hotstuff is activated
-// This value implicitly means that fork_database will prefer hotstuff blocks over dpos blocks
-constexpr uint32_t hs_dpos_irreversible_blocknum = std::numeric_limits<uint32_t>::max();
-
 namespace detail {
    struct block_header_state_legacy_common {
       uint32_t                          block_num = 0;
@@ -83,7 +79,7 @@ struct pending_block_header_state_legacy : public detail::block_header_state_leg
 /**
  *  @struct block_header_state
  *
- *  Algorithm for producer schedule change (pre-hostuff)
+ *  Algorithm for producer schedule change (pre-savanna)
  *     privileged contract -> set_proposed_producers(producers) ->
  *        global_property_object.proposed_schedule_block_num = current_block_num
  *        global_property_object.proposed_schedule           = producers

plugins/producer_plugin/producer_plugin.cpp

@@ -1898,8 +1898,8 @@ producer_plugin_impl::start_block_result producer_plugin_impl::start_block() {
    try {
       uint16_t blocks_to_confirm = 0;
 
-      auto block_state = chain.head_block_state_legacy(); // null means if is active
-      if (in_producing_mode() && block_state && block_state->dpos_irreversible_blocknum != hs_dpos_irreversible_blocknum) { // only if hotstuff not enabled
+      auto block_state = chain.head_block_state_legacy(); // null means savanna is active
+      if (in_producing_mode() && block_state) { // only if savanna not enabled
          // determine how many blocks this producer can confirm
          // 1) if it is not a producer from this node, assume no confirmations (we will discard this block anyway)
          // 2) if it is a producer on this node that has never produced, the conservative approach is to assume no