Merge r769809 from trunk:

* Improve and simplify the implementation of SSLProxyCheckPeerExpire by
  directly using X509_get_notBefore(), X509_get_notAfter() and
  X509_cmp_current_time().
  Thanks to jorton for the pointer.

Submitted by: rpluem
Reviewed/backported by: jim


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@776279 13f79535-47bb-0310-9956-ffa450edef68