Fix clippy

Author: wesleywiser

src/native/windows.rs

@@ -1,6 +1,6 @@
 use super::CurrentUser;
 use crate::cmd::KillFailedError;
-use failure::{bail, Error};
+use failure::Error;
 use std::fs::File;
 use std::path::Path;
 use windows_sys::Win32::Foundation::CloseHandle;

src/toolchain.rs

@@ -541,7 +541,7 @@ pub(crate) fn list_installed_toolchains(rustup_home: &Path) -> Result<Vec<Toolch
             #[cfg(feature = "unstable-toolchain-ci")]
             {
                 let (sha, alt) = if name.ends_with("-alt") {
-                    ((&name[..name.len() - 4]).to_string(), true)
+                    ((name[..name.len() - 4]).to_string(), true)
                 } else {
                     (name, false)
                 };