deps: remove OpenSSL git and travis configuration

OpenSSL is packaging its git and travis configuration files. Remove them, Node.js has its own.

This will remove .gitmodules, .gitattributes, .travis.yml, .travis-create-release.sh, .travis-apt-pin.preference from being present in https://github.com/nodejs/node/tree/master/deps/openssl/openssl

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• commit message follows commit guidelines