Remove some obsolete header comments/code.
Remove some obsolete header comments/code.

Shraddha512/rust-http,Shraddha512/rust-http,servo/rust-http,chris-morgan/rust-http,Shraddha512/rust-http,Shraddha512/rust-http,servo/rust-http,chris-morgan/rust-http,servo/rust-http,chris-morgan/rust-http,Shraddha512/rust-http,servo/rust-http,chris-morgan/rust-http