Path that evaluates to '/' results in error

[gergelyk]

This example:

extern crate path_absolutize;
use std::path::Path;
use path_absolutize::*;

fn main() {
    let p = Path::new("..");
    println!("{}", p.absolutize().unwrap().to_str().unwrap());
}

will panic when executable is run in cwd=/tmp. Expected result is / printed to stdout.
The same example works correctly when run in cwd=/tmp/foo.

[magiclen]

It should be fixed now.