Changed sha1 into bcrypt

| Q   | A
| --- | ---
| Doc fix? | yes
| New docs? | no
| Applies to | 2.2+ (bcrypt was introduced in 2.2)
| Fixed tickets | https://twitter.com/ircmaxell/status/412978651123023872

We loose some information, but I don't think that information is necessary. I also made the change without testing it, so: Needs some review!

/cc @ircmaxell @weaverryan