apply some simple clippy lints

src/bin/installer.rs

@@ -98,7 +98,7 @@ fn main() {
                 Ok(data) => {
                     config.files.push(redox_installer::FileConfig {
                         path: "pkg/id_ed25519.pub.toml".to_string(),
-                        data: data,
+                        data,
                         ..Default::default()
                     });
                     Some(path)
@@ -143,7 +143,7 @@ fn main() {
             None
         };
 
-        if let Some(path) = parser.args.get(0) {
+        if let Some(path) = parser.args.first() {
             if let Err(err) = redox_installer::install(
                 config,
                 path,

src/disk_wrapper.rs

@@ -70,7 +70,7 @@ impl DiskWrapper {
                 remaining,
                 self.block
                     .len()
-                    .checked_sub(offset.try_into().unwrap())
+                    .checked_sub(offset)
                     .unwrap(),
             );
 

src/lib.rs

@@ -45,7 +45,7 @@ fn get_target() -> String {
 /// Converts a password to a serialized argon2rs hash, understandable
 /// by redox_users. If the password is blank, the hash is blank.
 fn hash_password(password: &str) -> Result<String> {
-    if password != "" {
+    if !password.is_empty() {
         let salt = format!("{:X}", OsRng.next_u64());
         let config = argon2::Config::default();
         let hash = argon2::hash_encoded(password.as_bytes(), salt.as_bytes(), &config)?;
@@ -159,7 +159,7 @@ fn install_packages(config: &Config, dest: &str, cookbook: Option<&str>) {
             }
         }
     } else {
-        for (packagename, _package) in &config.packages {
+        for packagename in config.packages.keys() {
             println!("Installing package from remote: {}", packagename);
             library
                 .install(vec![pkg::PackageName::new(packagename).unwrap()])
@@ -422,10 +422,8 @@ where
         format!("/tmp/redox_installer_{}", process::id())
     };
 
-    if cfg!(not(target_os = "redox")) {
-        if !Path::new(&mount_path).exists() {
-            fs::create_dir(&mount_path)?;
-        }
+    if cfg!(not(target_os = "redox")) && !Path::new(&mount_path).exists() {
+        fs::create_dir(&mount_path)?;
     }
 
     let ctime = SystemTime::now().duration_since(UNIX_EPOCH)?;