Rust 1.54.0 lints (#2483)

## Issue Addressed

N/A

## Proposed Changes

- Removing a bunch of unnecessary references
- Updated `Error::VariantError` to `Error::Variant`
- There were additional enum variant lints that I ignored, because I thought our variant names were fine
- removed `MonitoredValidator`'s `pubkey` field, because I couldn't find it used anywhere. It looks like we just use the string version of the pubkey (the `id` field) if there is no index

## Additional Info



Co-authored-by: realbigsean <seananderson33@gmail.com>

account_manager/src/common.rs

@@ -19,7 +19,7 @@ pub fn read_mnemonic_from_cli(
             .map_err(|e| format!("Unable to read {:?}: {:?}", path, e))
             .and_then(|bytes| {
                 let bytes_no_newlines: PlainText = strip_off_newlines(bytes).into();
-                let phrase = from_utf8(&bytes_no_newlines.as_ref())
+                let phrase = from_utf8(bytes_no_newlines.as_ref())
                     .map_err(|e| format!("Unable to derive mnemonic: {:?}", e))?;
                 Mnemonic::from_phrase(phrase, Language::English).map_err(|e| {
                     format!(

account_manager/src/validator/exit.rs

@@ -51,7 +51,7 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                 .long(BEACON_SERVER_FLAG)
                 .value_name("NETWORK_ADDRESS")
                 .help("Address to a beacon node HTTP API")
-                .default_value(&DEFAULT_BEACON_NODE)
+                .default_value(DEFAULT_BEACON_NODE)
                 .takes_value(true),
         )
         .arg(

account_manager/src/validator/slashing_protection.rs

@@ -87,8 +87,8 @@ pub fn cli_run<T: EthSpec>(
 
     match matches.subcommand() {
         (IMPORT_CMD, Some(matches)) => {
-            let import_filename: PathBuf = clap_utils::parse_required(&matches, IMPORT_FILE_ARG)?;
-            let minify: bool = clap_utils::parse_required(&matches, MINIFY_FLAG)?;
+            let import_filename: PathBuf = clap_utils::parse_required(matches, IMPORT_FILE_ARG)?;
+            let minify: bool = clap_utils::parse_required(matches, MINIFY_FLAG)?;
             let import_file = File::open(&import_filename).map_err(|e| {
                 format!(
                     "Unable to open import file at {}: {:?}",
@@ -199,8 +199,8 @@ pub fn cli_run<T: EthSpec>(
             Ok(())
         }
         (EXPORT_CMD, Some(matches)) => {
-            let export_filename: PathBuf = clap_utils::parse_required(&matches, EXPORT_FILE_ARG)?;
-            let minify: bool = clap_utils::parse_required(&matches, MINIFY_FLAG)?;
+            let export_filename: PathBuf = clap_utils::parse_required(matches, EXPORT_FILE_ARG)?;
+            let minify: bool = clap_utils::parse_required(matches, MINIFY_FLAG)?;
 
             if !slashing_protection_db_path.exists() {
                 return Err(format!(

account_manager/src/wallet/create.rs

@@ -114,7 +114,7 @@ pub fn cli_run(matches: &ArgMatches, wallet_base_dir: PathBuf) -> Result<(), Str
         Language::English,
     );
 
-    let wallet = create_wallet_from_mnemonic(matches, &wallet_base_dir.as_path(), &mnemonic)?;
+    let wallet = create_wallet_from_mnemonic(matches, wallet_base_dir.as_path(), &mnemonic)?;
 
     if let Some(path) = mnemonic_output_path {
         create_with_600_perms(&path, mnemonic.phrase().as_bytes())
@@ -168,7 +168,7 @@ pub fn create_wallet_from_mnemonic(
             if !path.exists() {
                 // To prevent users from accidentally supplying their password to the PASSWORD_FLAG and
                 // create a file with that name, we require that the password has a .pass suffix.
-                if path.extension() != Some(&OsStr::new("pass")) {
+                if path.extension() != Some(OsStr::new("pass")) {
                     return Err(format!(
                         "Only creates a password file if that file ends in .pass: {:?}",
                         path
@@ -189,7 +189,7 @@ pub fn create_wallet_from_mnemonic(
         .create_wallet(
             wallet_name,
             wallet_type,
-            &mnemonic,
+            mnemonic,
             wallet_password.as_bytes(),
         )
         .map_err(|e| format!("Unable to create wallet: {:?}", e))?;

account_manager/src/wallet/recover.rs

@@ -71,7 +71,7 @@ pub fn cli_run(matches: &ArgMatches, wallet_base_dir: PathBuf) -> Result<(), Str
 
     let mnemonic = read_mnemonic_from_cli(mnemonic_path, stdin_inputs)?;
 
-    let wallet = create_wallet_from_mnemonic(matches, &wallet_base_dir.as_path(), &mnemonic)
+    let wallet = create_wallet_from_mnemonic(matches, wallet_base_dir.as_path(), &mnemonic)
         .map_err(|e| format!("Unable to create wallet: {:?}", e))?;
 
     println!("Your wallet has been successfully recovered.");