openssl: Fix compilation with OPENSSL_API_COMPAT=0x10100000L
With OPENSSL_API_COMPAT=0x10100000L (OpenSSL 1.1 API), the cleanup
functions are unavailable (they're no-ops anyway in OpenSSL 1.1). The
replacements for SSL_load_error_strings, SSLeay_add_ssl_algorithms, and
OpenSSL_add_all_algorithms are called automatically [1][2]. SSLeay() is
now called OpenSSL_version_num().