Drop null_logger (#6013)

* Drop null_logger

lcli/src/transition_blocks.rs

@@ -66,13 +66,14 @@ use beacon_chain::{
 };
 use clap::ArgMatches;
 use clap_utils::{parse_optional, parse_required};
-use environment::{null_logger, Environment};
+use environment::Environment;
 use eth2::{
     types::{BlockId, StateId},
     BeaconNodeHttpClient, SensitiveUrl, Timeouts,
 };
 use eth2_network_config::Eth2NetworkConfig;
 use log::{debug, info};
+use sloggers::{null::NullLoggerBuilder, Build};
 use ssz::Encode;
 use state_processing::state_advance::complete_state_advance;
 use state_processing::{
@@ -196,7 +197,9 @@ pub fn run<E: EthSpec>(
     let store = HotColdDB::open_ephemeral(
         <_>::default(),
         spec.clone(),
-        null_logger().map_err(|e| format!("Failed to create null_logger: {:?}", e))?,
+        NullLoggerBuilder
+            .build()
+            .map_err(|e| format!("Error on NullLoggerBuilder: {:?}", e))?,
     )
     .map_err(|e| format!("Failed to create ephemeral store: {:?}", e))?;
     let store = Arc::new(store);