fixing case where delegate_hash isn't available

[pbrumm]

and this was raising an error. sidekiq + delayed_mailer and yaml

we use sidekiq's action_mailer extensions to add a delay
https://github.com/mperham/sidekiq/blob/v5.2.7/lib/sidekiq/extensions/action_mailer.rb#L33

which serializes yaml and then restores it when worker starts with
https://github.com/ruby/psych/blob/master/lib/psych/visitors/to_ruby.rb#L394
which hits your init_with and raises exception on some of the cleanup code.

so this pull fixes that by rescuing.

some inspection could also take place but the this seemed more risky.