ICE if there are misspellings in crate-level documentation

[sfackler]

src/lib.rs:1:1: 1:82 error: internal compiler error: unprocessed lint misspellings at unknown node (id=0): misspelled words: Postgres, frontend, Postgre
src/lib.rs:1 //! Rust-Postgres is a pure-Rust frontend for the popular PostgreSQL database. It
             ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

[huonw]

Not (entirely) the fault of spellck: rust-lang/rust#16702 :(

(Leaving this open for now.)