Fix Issue 2389:  Self signed certificate expiry causes silent send/receive failure.

With this fix, a CertPathValidatorException or CertificateException will
create a "Certificate error:  Check your server settings" notification
in the status bar.  When the user clicks on the notification, they are
taken to the appropriate server settings screen where they can review their
settings and can accept a different server certificate.
Merge remote-tracking branch 'zjw/issue_2389_cert_error_notice2'

* zjw/issue_2389_cert_error_notice2:
  Fix Issue 2389:  Self signed certificate expiry causes silent send/receive failure.