fixed updating password action when password is blank

When resetting a password if I submit the form with the password fields on blank I get this error:

![screen shot 2013-07-24 at 6 21 41 pm](https://f.cloud.github.com/assets/469507/852641/f38d11f0-f4b7-11e2-91ea-16934dda45a8.png)

I did a little patch to fix this.