Merge branch 'tr/send-email-ssl'

SSL-related options were not passed correctly to underlying socket
layer in "git send-email".

* tr/send-email-ssl:
  send-email: set SSL options through IO::Socket::SSL::set_client_defaults
  send-email: --smtp-ssl-cert-path takes an argument
  send-email: pass Debug to Net::SMTP::SSL::new