Cherry-pick #9566 to 6.x: [Heartbeat] Handle TLS certs missing notBefore/notAfter#9758

Merged

andrewvc merged 1 commit intoelastic:6.xfrom andrewvc:backport_9566_6.x

Jan 2, 2019

+171-22

Commits on Dec 31, 2018

[Heartbeat] Handle TLS certs missing notBefore/notAfter (elastic#9566 )
andrewvc
committed