Remove superfluous code: `HttpError` implicitly converts to `IoError` in the `try!` macro.
Remove superfluous code: `HttpError` implicitly converts to `IoError` in
the `try!` macro.

abonander/multipart-async,abonander/multipart-async,cybergeek94/multipart,cybergeek94/multipart,abonander/multipart-async