Pool blocks when connection settings is wrong

[s-panferov]

I have just looked at r2d2-postgres and saw the problem:

let manager = PostgresPoolManager::new("postgres://postgres@localhost/wrong", NoSsl);
let config = r2d2::Config {
    pool_size: 5,
    test_on_check_out: true,
    ..std::default::Default::default()
};

let handler = r2d2::NoopErrorHandler;
let pool = r2d2::Pool::new(config, manager, handler).unwrap();
pool.get().unwrap(); // blocks forever

[sfackler]

Yep, it's a bummer. This and some other improvements are blocked on rust-lang/rust#17094.

[sfackler]

This has been fixed in the most recent r2d2 releases.