Switch to foreign_types

openssl/Cargo.toml

openssl/src/asn1.rs

openssl/src/bn.rs

openssl/src/dh.rs

openssl/src/dsa.rs

openssl/src/ec.rs

openssl/src/lib.rs

openssl/src/macros.rs

openssl/src/ocsp.rs

openssl/src/pkcs12.rs

openssl/src/pkey.rs

openssl/src/rsa.rs

openssl/src/sign.rs

openssl/src/ssl/mod.rs

openssl/src/ssl/tests/mod.rs

openssl/src/stack.rs

openssl/src/string.rs

openssl/src/types.rs

openssl/src/verify.rs

openssl/src/x509/mod.rs