SMTP configuration not used

[welearnednothing]

When configuring the mail settings to use SMTP, the settings are being applied to ActionMailer::Base as a hash with string keys, which at mail time aren't recognized and the defaults are used instead (sitting alongside the configured options as symbolized keys).

For example. if I add

puts mail.to_yaml

into notification_mailer.rb, I'll see the following for SMTP settings:

'@delivery_method': !ruby/object:Mail::SMTP
  settings:
    :address: localhost
    :port: 25
    :domain: localhost.localdomain
    :user_name:
    :password:
    :authentication:
    :enable_starttls_auto: true
    :openssl_verify_mode:
    :ssl:
    :tls:
    address: my.mail.com
    port: 25
    domain: disney.com
    user_name:
    password:
    authentication: none
    enable_starttls_auto: false

where the symbolized keys will be used, not the string keys from the config.

Given that default_url_options for the mailer are symbolized, it seems like we should be doing the same for SMTP options. PR to follow.