Do not duplicate SIZE extension

[lukebakken]

Fixes #55

[lukebakken]

@a-marcellini - please test this fix in your environment. Thanks a lot!

[a-marcellini]

The behaviour has definitely changed:

$ telnet localhost 2525
Trying ::1...
Connected to localhost.
Escape character is '^]'.
220 mail.local ESMTP rabbit_email_handler
EHLO COppa
250-mail.local
250-AUTH PLAIN LOGIN
250-SIZE 41943040
250-8BITMIME
250-PIPELINING
250 SMTPUTF8

And now postfix delivers the message and rabbit doesn't bounce it back.

Oct 20 15:00:41 mailserver postfix-in/qmgr[360]: D8CEE2A4061: from=<address1@mail.local>, size=13760367, nrcpt=1 (queue active)
...
Oct 20 15:00:41 mailserver postfix-in/smtp[490]: D8CEE2A4061: to=<address2@mail.local>, relay=rabbitmq[172.23.0.5]:2525, delay=4.9, delays=4.3/0.02/0.05/0.52, dsn=2.0.0, status=sent (250 015e8da796b65556d8831a0044a25f43)

So, it seems it's working!

[lukebakken]

@a-marcellini thank you for testing.

[lukebakken]

@a-marcellini - https://github.com/gotthardp/rabbitmq-email/releases/tag/v1.1.1