Exclude $ for salt value

[loafoe]

See #74

[zoomoid]

While adding a validation for this should be easy, your usage example generally relies on random_password resources. If you just puzzle these parts together, and throw an error from inside this provider, it might be intransparent why it failed, because no user actually created that salt consciously. If you just "expect" the random_password to be "correct", and then have the provider error, this might confusion for the actual user.

Those are just my few cents from a UX standpoint, I generally welcome the change in terms of safety :)