Remove toolchain directory if initial toolchain install fails
Remove toolchain directory if initial toolchain install fails

If initial toolchain installation fails it leaves behind a directory,
which confuses rustup into thinking it's installed.

rust-lang/rustup,inejge/rustup.rs,rust-lang/rustup,Boddlnagg/rustup.rs,nodakai/rustup.rs,polonez/rustup.rs,inejge/rustup.rs,theindigamer/rustup.rs,polonez/rustup.rs,theindigamer/rustup.rs,rust-lang/rustup,Boddlnagg/rustup.rs,polonez/rustup.rs,rust-lang/rustup,Boddlnagg/rustup.rs,inejge/rustup.rs,Boddlnagg/rustup.rs,polonez/rustup.rs,nodakai/rustup.rs,inejge/rustup.rs,theindigamer/rustup.rs,nodakai/rustup.rs,Boddlnagg/rustup.rs,theindigamer/rustup.rs,inejge/rustup.rs,nodakai/rustup.rs,theindigamer/rustup.rs,rust-lang/rustup,polonez/rustup.rs,nodakai/rustup.rs