[erlang-patches] EEP Light: Option to override private key lookup when using Erlang ssh client

[Vipin Nair]

> Great!  If there also is documentation and a test case the likelihood of
> acceptance is higher :)

Hans, I have made the suggested changes and sent a pull request[1].
Surprisingly, there were no tests for key callback. I have added tests for
callback module as well as callback module options. Please review.

[1]: https://github.com/erlang/otp/pull/892

-- 
Regards,
Vipin