crypto: enable FIPS only when configured with it

Do not rely on `OPENSSL_FIPS` in `node_crypto.cc` when building with
shared FIPS-enabled OpenSSL library. Enable FIPS in core only when
configured with `--openssl-fips`.

Fix: https://github.com/nodejs/node/issues/3077
PR-URL: https://github.com/nodejs/node/pull/3153


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>