title: How to fix expired client cert in docker-machine
body: <p>Doing a <code>docker-machine ls</code> a got the unexpected <code>Unable to query docker version: Get https://x.x.x.x:2376/v1.15/version: x509: certificate has expired or is not yet valid</code> for every machine.  </p>
  
  <p>I hadn't done anything recently.  Looking on SO, I tried some common culprits, VPN, virus, weird clock issues, etc.  None of that applied.  How can I fix make them useable again (via the <code>docker-machine</code> interface)? </p>
  
  <p>Using Docker for Mac, 17.12.0-ce-49</p>