Possible double close in code

[Barry Steyn <barry.steyn@gmail.com>]

Dear Colin

This was recently brought to my attention by a someone who used a C code checking tool. The issue that was reported was a possible double close of the readfrom stream in the file scrypt/scrypt-1.1.6/lib/util/readpass.c

You can view the diff that was suggested below. 

https://github.com/mscdex/node-scrypt/commit/8e489e8b7a1d7c42b99b0ee10e239ee16ebde76b

I refuse to touch your code, and so if  you deem it worth while, you can change it.

Regards

Barry