[FIX] ir.mail_server: SMTP user and pass should be passed as bytes to login()
[FIX] ir.mail_server: SMTP user and pass should be passed as bytes to login()

Passing a unicode used to work in Python 2.5 but that
changed in 2.6 due to a change in the hmac module.
In any case the various RFCs that describe such
authentication mechanism do specify that UTF-8 encoded
values should be used, so we should be safe coercing
the user and passsword to UTF-8 bytes strings.
And of course it should not change anything for
the ASCII passwords out there anyway.

For references, see:
- Zope bug https://bugs.launchpad.net/zope.sendmail/+bug/597143
- Python issue http://bugs.python.org/issue5285
- http://tools.ietf.org/html/draft-ietf-sasl-crammd5-10#section-4


akretion/openerp-server,akretion/openerp-server,akretion/openerp-server