rust2018: remove extern crate

Signed-off-by: Levente Kurusa <lkurusa@acm.org>

src/devices.rs

@@ -5,6 +5,8 @@
 use std::io::{Read, Write};
 use std::path::PathBuf;
 
+use log::*;
+
 use crate::error::*;
 use crate::error::ErrorKind::*;
 

src/hierarchies.rs

@@ -8,6 +8,8 @@ use std::io::BufRead;
 use std::io::BufReader;
 use std::path::{Path, PathBuf};
 
+use log::*;
+
 use crate::blkio::BlkIoController;
 use crate::cpu::CpuController;
 use crate::cpuacct::CpuAcctController;

src/lib.rs

@@ -1,5 +1,4 @@
-#[macro_use]
-extern crate log;
+use log::*;
 
 use std::fs::File;
 use std::io::{BufRead, BufReader, Write};