Fix a couple of warnings

src/dnsd/main.rs

@@ -1,7 +1,7 @@
 #[macro_use]
 extern crate log;
 
-use anyhow::{Context, Error, Result};
+use anyhow::{Context, Result};
 use event::EventQueue;
 use ioslice::IoSlice;
 use libredox::Fd;

src/dnsd/scheme.rs

@@ -318,7 +318,7 @@ impl<'q> Dnsd<'q> {
     const REQUEST_TIMEOUT_S: i64 = 30;
     const TIME_EVENT_TIMEOUT_S: i64 = 5;
 
-    pub fn new(dns_file: File, time_file: File, queue: &'q EventQueue<EventSource>) -> Dnsd {
+    pub fn new(dns_file: File, time_file: File, queue: &'q EventQueue<EventSource>) -> Self {
         Dnsd {
             dns_file,
             time_file,

src/smolnetd/main.rs

@@ -7,11 +7,7 @@ extern crate redox_netstack;
 extern crate smoltcp;
 extern crate syscall;
 
-use std::cell::RefCell;
-use std::fs::File;
-use std::os::unix::io::{FromRawFd, RawFd};
 use std::process;
-use std::rc::Rc;
 
 use anyhow::{anyhow, bail, Context, Result};
 use event::{EventFlags, EventQueue};