edition: Fill in macro imports

Macros were previously imported through `#[macro_use] extern crate`,
which is basically a glob import of all macros from the crate. As of
2018 edition of Rust, `extern crate` is no longer required and macros
are imported individually like any other item from a dependency. This CL
fills in all the appropriate macro imports that will allow us to remove
our use of `extern crate` in a subsequent CL.

TEST=cargo check --all-features --tests
TEST=kokoro

Change-Id: If2ec08b06b743abf5f62677c6a9927c3d5d90a54
Reviewed-on: https://chromium-review.googlesource.com/1565546
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: David Tolnay <dtolnay@chromium.org>

1 files changed, 2 insertions, 2 deletions

diff --git a/devices/src/virtio/block.rs b/devices/src/virtio/block.rs
index 023e1df..0a22e32 100644
--- a/devices/src/virtio/block.rs
+++ b/devices/src/virtio/block.rs
@@ -18,8 +18,8 @@ use sync::Mutex;
 use sys_util::Error as SysError;
 use sys_util::Result as SysResult;
 use sys_util::{
-    EventFd, FileSetLen, FileSync, GuestAddress, GuestMemory, GuestMemoryError, PollContext,
-    PollToken, PunchHole, TimerFd, WriteZeroes,
+    error, info, warn, EventFd, FileSetLen, FileSync, GuestAddress, GuestMemory, GuestMemoryError,
+    PollContext, PollToken, PunchHole, TimerFd, WriteZeroes,
 };
 
 use data_model::{DataInit, Le16, Le32, Le64};