Remove workaround for error-chain
Remove workaround for error-chain

rust-lang/rustup,rust-lang/rustup,inejge/rustup.rs,inejge/rustup.rs,rust-lang/rustup,nodakai/rustup.rs,rust-lang/rustup,nodakai/rustup.rs,nodakai/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs,nodakai/rustup.rs,inejge/rustup.rs,rust-lang/rustup,inejge/rustup.rs