deps: refactor openssl.gyp

Updated gyp has "else if" syntax in condition. Use this for
target_arch and OS switches. Several sources, defines, rules and
libraries variables moved to gypi files.

PR-URL: https://github.com/iojs/io.js/pull/1325


Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>