Default to system ca-certificates.crt if none is specified (#10857)

Co-Authored-By: Yamagishi Kazutoshi <ykzts@desire.sh>

Co-authored-by: Yamagishi Kazutoshi <ykzts@desire.sh>

config/environments/production.rb

@@ -105,7 +105,7 @@ Rails.application.configure do
     :password             => ENV['SMTP_PASSWORD'].presence,
     :domain               => ENV['SMTP_DOMAIN'] || ENV['LOCAL_DOMAIN'],
     :authentication       => ENV['SMTP_AUTH_METHOD'] == 'none' ? nil : ENV['SMTP_AUTH_METHOD'] || :plain,
-    :ca_file              => ENV['SMTP_CA_FILE'].presence,
+    :ca_file              => ENV['SMTP_CA_FILE'].presence || '/etc/ssl/certs/ca-certificates.crt',
     :openssl_verify_mode  => ENV['SMTP_OPENSSL_VERIFY_MODE'],
     :enable_starttls_auto => ENV['SMTP_ENABLE_STARTTLS_AUTO'] || true,
     :tls                  => ENV['SMTP_TLS'].presence,