clippy: Suppress warning from protoc_rust generated code

Protoc_rust emits this into every file it generates:

    #![cfg_attr(feature = "cargo-clippy", allow(clippy))]

which is the old style of tool attribute. It is deprecated in favor of
actual tool attributes that stabilized in rust 1.31.

    #![allow(clippy::all)]

Without this PR, the warning when running bin/clippy looks like:

    warning: lint name `clippy` is deprecated and may not have an effect in the future.
     --> /chromiumos/src/platform/crosvm/target/debug/build/protos/out/trunks/interface.rs:6:10
      |
    6 | #![cfg_attr(feature = "cargo-clippy", allow(clippy))]
      |                                             ^^^^^^
      |
      = note: #[warn(renamed_and_removed_lints)] on by default

TEST=bin/clippy

Change-Id: I1a484379a8f53d76d3667590cd8458588492d2b1
Reviewed-on: https://chromium-review.googlesource.com/1567849
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>

1 files changed, 6 insertions, 0 deletions

diff --git a/protos/build.rs b/protos/build.rs
index fa839ca..b510e54 100644
--- a/protos/build.rs
+++ b/protos/build.rs
@@ -98,8 +98,14 @@ fn protoc<P: AsRef<Path>>(module: &str, input_path: P, mut out: &File) -> Result
     })?;
 
     // Write out a `mod` that refers to the generated module.
+    //
+    // The lint suppression is because protoc-rust emits
+    //   #![cfg_attr(feature = "cargo-clippy", allow(clippy))]
+    // which still works but is deprecated in favor of tool attributes:
+    //   #![allow(clippy::all)].
     let file_stem = input_path.file_stem().unwrap().to_str().unwrap();
     writeln!(out, "#[path = \"{}/{}.rs\"]", out_dir, file_stem)?;
+    writeln!(out, "#[allow(renamed_and_removed_lints)]")?;
     writeln!(out, "pub mod {};", module)?;
 
     Ok(())