rust: update to 2021 edition

Signed-off-by: Aleksa Sarai <[email protected]>

Cargo.toml

@@ -26,7 +26,7 @@ readme = "README.md"
 
 keywords = ["file", "fs", "security", "linux"]
 categories = ["filesystem"]
-edition = "2018"
+edition = "2021"
 
 [badges]
 maintenance = { status = "experimental" }

src/capi/utils.rs

@@ -20,7 +20,6 @@ use crate::error::{self, Error};
 
 use std::{
     cmp,
-    convert::TryInto,
     ffi::{CStr, CString, OsStr},
     io::Error as IOError,
     os::unix::ffi::OsStrExt,

src/procfs.rs

@@ -27,7 +27,6 @@ use crate::{
 };
 
 use std::{
-    convert::TryFrom,
     fs::File,
     os::fd::AsRawFd,
     os::unix::fs::MetadataExt,

src/tests/common/mntns.rs

@@ -66,9 +66,9 @@ pub(crate) fn mount<P: AsRef<Path>>(dst: P, ty: MountType) -> Result<(), Error>
     let ret = match ty {
         MountType::Tmpfs => unsafe {
             libc::mount(
-                CString::new("")?.as_ptr(),
+                c"".as_ptr(),
                 dst_path.as_ptr(),
-                CString::new("tmpfs")?.as_ptr(),
+                c"tmpfs".as_ptr(),
                 0,
                 ptr::null(),
             )