linux機でインストールできたけど？
環境とエラーログ無いとpyOpenSSLの件について答えれれ無い。

sudo pip3 install pyOpenSSL

[sudo] 　　　　のパスワード:
Collecting pyOpenSSL

pyOpenSSL
Found existing installation: idna 2.0
Uninstalling idna-2.0:
Successfully uninstalled idna-2.0
Running setup.py install for pycparser ... done
Found existing installation: cryptography 1.2.3
Uninstalling cryptography-1.2.3:
Successfully uninstalled cryptography-1.2.3
Successfully installed asn1crypto-0.23.0 cffi-1.11.1 cryptography-2.0.3 idna-2.6 pyOpenSSL-17.3.0 pycparser-2.18