Add workaround for platforms where injecting pyopenssl to urllib3 (#3990)
Add workaround for platforms where injecting pyopenssl to urllib3 (#3990)

fails with requests package (Ubuntu Trusty)
jsha/letsencrypt,jsha/letsencrypt,stweil/letsencrypt,lmcro/letsencrypt,letsencrypt/letsencrypt,lmcro/letsencrypt,stweil/letsencrypt,letsencrypt/letsencrypt