Avoiding false Dialyzer warnings for NIFs

[Björn Gustavsson]

I have implemented a new erlang:nif_error/1 BIF that can
be used in the stub for NIFs to avoid false Dialyzer
warnings:

http://github.com/bjorng/otp/commit/826c9574776ae931917e55d441ec0cfcb0acaf84

In a second commit, I have modified the crypto
module to use erlang:nif_error/1.

I have run the crypto test suite, but I have not yet
verified that the false Dialyzer warnings disappear.

Feedback welcome.


The branch can be fetched like this:

git fetch git://github.com/bjorng/otp.git bg/nif_error

-- 
Björn Gustavsson, Erlang/OTP, Ericsson AB