Add message_id to AM payload and don't send bcc and cc if they were not sent.

actionmailer/lib/action_mailer/base.rb

@@ -426,14 +426,13 @@ module ActionMailer #:nodoc:
       end
 
       def set_payload_for_mail(payload, mail) #:nodoc:
+        payload[:message_id] = mail.message_id
         payload[:subject]    = mail.subject
         payload[:to]         = mail.to
         payload[:from]       = mail.from
-        payload[:bcc]      = mail.bcc
-        payload[:cc]       = mail.cc
-        payload[:reply_to] = mail.reply_to
+        payload[:bcc]        = mail.bcc if mail.bcc.present?
+        payload[:cc]         = mail.cc  if mail.cc.present?
         payload[:date]       = mail.date
-        payload[:body]     = mail.body.encoded
         payload[:mail]       = mail.encoded
       end