Bug 1889238 - Remove redundant imports from xpcom crates. r=xpcom-reviewers,emilio

Differential Revision: https://phabricator.services.mozilla.com/D206426

xpcom/rust/gecko_logger/src/lib.rs

@@ -10,7 +10,6 @@ extern crate lazy_static;
 use app_services_logger::{AppServicesLogger, LOGGERS_BY_TARGET};
 use log::Log;
 use log::{Level, LevelFilter};
-use std::boxed::Box;
 use std::collections::HashMap;
 use std::ffi::{CStr, CString};
 use std::os::raw::c_char;

xpcom/rust/gtest/moz_task/test.rs

@@ -2,7 +2,6 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
-use moz_task;
 use std::{
     future::Future,
     pin::Pin,

xpcom/rust/xpcom/src/refptr.rs

@@ -3,7 +3,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 use crate::interfaces::nsISupports;
-use libc;
 use nserror::{nsresult, NS_OK};
 use std::cell::Cell;
 use std::convert::TryInto;