[FIX] mail: missing user attribute

Allow customization to retrieve the user used to authenticate by adding
the user attribute.

opw-4059147

closes odoo#174208

Signed-off-by: Denis Ledoux (dle) <dle@odoo.com>

odoo/addons/base/models/ir_mail_server.py

@@ -55,7 +55,7 @@ def __init__(self, server, port, encryption, context=None):
 SMTP_ATTRIBUTES = [
  'auth', 'auth_cram_md5', 'auth_login', 'auth_plain', 'close', 'data', 'docmd', 'ehlo', 'ehlo_or_helo_if_needed',
  'expn', 'from_filter', 'getreply', 'has_extn', 'login', 'mail', 'noop', 'putcmd', 'quit', 'rcpt', 'rset',
- 'send_message', 'sendmail', 'set_debuglevel', 'smtp_from', 'starttls', 'verify', '_host',
+ 'send_message', 'sendmail', 'set_debuglevel', 'smtp_from', 'starttls', 'user', 'verify', '_host',
 ]
 for name in SMTP_ATTRIBUTES:
  setattr(SMTPConnection, name, make_wrap_property(name))