The value of gunicorn's option 'cert_reqs` for client-cert requirement
does not take a boolean, but rather `ssl.CERT_REQUIRED` which is `2`.
Story: 2006660
Task: 36916
SecurityImpact: CVE-2019-17134
Change-Id: I5619f5e40d7c9a2ee7741bf4664c0d2d08963992