Erase inactive votes cache after election stop / finish

... and for forks elections

nano/node/active_transactions.cpp

@@ -1126,6 +1126,15 @@ nano::gap_information nano::active_transactions::find_inactive_votes_cache (nano
 	}
 }
 
+void nano::active_transactions::erase_inactive_votes_cache (nano::block_hash const & hash_a)
+{
+	auto existing (inactive_votes_cache.get<1> ().find (hash_a));
+	if (existing != inactive_votes_cache.get<1> ().end ())
+	{
+		inactive_votes_cache.get<1> ().erase (existing);
+	}
+}
+
 size_t nano::active_transactions::dropped_elections_cache_size ()
 {
 	nano::lock_guard<std::mutex> guard (mutex);

nano/node/active_transactions.hpp

@@ -134,6 +134,7 @@ class active_transactions final
 	void add_confirmed (nano::election_status const &, nano::qualified_root const &);
 	void add_inactive_votes_cache (nano::block_hash const &, nano::account const &);
 	nano::gap_information find_inactive_votes_cache (nano::block_hash const &);
+	void erase_inactive_votes_cache (nano::block_hash const &);
 	nano::node & node;
 	std::mutex mutex;
 	std::chrono::seconds const long_election_threshold;

nano/node/election.cpp

@@ -298,6 +298,7 @@ void nano::election::clear_blocks ()
 		(void)erased;
 		// clear_blocks () can be called in active_transactions::publish () before blocks insertion if election was confirmed
 		assert (erased == 1 || confirmed);
+		node.active.erase_inactive_votes_cache (hash);
 		// Notify observers about dropped elections & blocks lost confirmed elections
 		if (stopped || hash != winner_hash)
 		{

nano/node/node.cpp

@@ -557,6 +557,12 @@ void nano::node::process_fork (nano::transaction const & transaction_a, std::sha
 		std::shared_ptr<nano::block> ledger_block (ledger.forked_block (transaction_a, *block_a));
 		if (ledger_block && !block_confirmed_or_being_confirmed (transaction_a, ledger_block->hash ()))
 		{
+			// Clear inactive votes cache for forks
+			{
+				nano::lock_guard<std::mutex> lock (active.mutex);
+				active.erase_inactive_votes_cache (ledger_block->hash ());
+				active.erase_inactive_votes_cache (block_a->hash ());
+			}
 			std::weak_ptr<nano::node> this_w (shared_from_this ());
 			if (!active.start (ledger_block, false, [this_w, root](std::shared_ptr<nano::block>) {
 				    if (auto this_l = this_w.lock ())