Fix clippy warnings (#813)

* Clippy account manager

* Clippy account_manager

* Clippy beacon_node/beacon_chain

* Clippy beacon_node/client

* Clippy beacon_node/eth1

* Clippy beacon_node/eth2-libp2p

* Clippy beacon_node/genesis

* Clippy beacon_node/network

* Clippy beacon_node/rest_api

* Clippy beacon_node/src

* Clippy beacon_node/store

* Clippy eth2/lmd_ghost

* Clippy eth2/operation_pool

* Clippy eth2/state_processing

* Clippy eth2/types

* Clippy eth2/utils/bls

* Clippy eth2/utils/cahced_tree_hash

* Clippy eth2/utils/deposit_contract

* Clippy eth2/utils/eth2_interop_keypairs

* Clippy eth2/utils/eth2_testnet_config

* Clippy eth2/utils/lighthouse_metrics

* Clippy eth2/utils/ssz

* Clippy eth2/utils/ssz_types

* Clippy eth2/utils/tree_hash_derive

* Clippy lcli

* Clippy tests/beacon_chain_sim

* Clippy validator_client

* Cargo fmt

validator_client/src/attestation_service.rs

@@ -194,8 +194,9 @@ impl<T: SlotClock + 'static, E: EthSpec> AttestationService<T, E> {
             .into_iter()
             .for_each(|duty| {
                 if let Some(committee_index) = duty.attestation_committee_index {
-                    let validator_duties =
-                        committee_indices.entry(committee_index).or_insert(vec![]);
+                    let validator_duties = committee_indices
+                        .entry(committee_index)
+                        .or_insert_with(|| vec![]);
 
                     validator_duties.push(duty);
                 }

validator_client/src/duties_service.rs

@@ -443,7 +443,7 @@ impl<T: SlotClock + 'static, E: EthSpec> DutiesService<T, E> {
     /// Attempt to download the duties of all managed validators for the given `epoch`.
     fn update_epoch(self, epoch: Epoch) -> impl Future<Item = (), Error = String> {
         let service_1 = self.clone();
-        let service_2 = self.clone();
+        let service_2 = self;
 
         let pubkeys = service_1.validator_store.voting_pubkeys();
         service_1

validator_client/src/validator_directory.rs

@@ -384,12 +384,11 @@ mod tests {
             "withdrawal keypair should be as expected"
         );
         assert!(
-            created_dir
+            !created_dir
                 .deposit_data
                 .clone()
                 .expect("should have data")
-                .len()
-                > 0,
+                .is_empty(),
             "should have some deposit data"
         );