Rust-toolchain file overrides rust version set in matrix

When a repo contains a rust-toolchain file, Travis’ build matrix does not install the requested rust version, and always uses the version defined in the rust-toolchain file instead.

Is there a hook I could use (before_install or strh like that) to remove the rust-toolchain file from the CI workspace before the toolchain installation? Or, maybe there’s other workaround for this issue?