remove license preamble from node-template (#4699)

substrate/bin/node-template/runtime/build.rs

-// Copyright 2019-2020 Parity Technologies (UK) Ltd.
-// This file is part of Substrate.
-
-// Substrate is free software: you can redistribute it and/or modify
-// it under the terms of the GNU General Public License as published by
-// the Free Software Foundation, either version 3 of the License, or
-// (at your option) any later version.
-
-// Substrate is distributed in the hope that it will be useful,
-// but WITHOUT ANY WARRANTY; without even the implied warranty of
-// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-// GNU General Public License for more details.
-
-// You should have received a copy of the GNU General Public License
-// along with Substrate.  If not, see <http://www.gnu.org/licenses/>.
-
 use wasm_builder_runner::{build_current_project_with_rustflags, WasmBuilderSource};
 
 fn main() {

substrate/bin/node-template/src/main.rs

 //! Substrate Node Template CLI library.
-
 #![warn(missing_docs)]
-#![warn(unused_extern_crates)]
 
 mod chain_spec;
 #[macro_use]