Better cache cleanup

src/p2pool.cpp

@@ -302,7 +302,9 @@ void p2pool::handle_miner_data(MinerData& data)
 	);
 
 	// Tx secret keys from all miners change every block, so cache can be cleared here
-	clear_crypto_cache();
+	if (m_sideChain->precalcFinished()) {
+		clear_crypto_cache();
+	}
 
 	if (!is_main_thread()) {
 		update_block_template_async();