If the recipients are passed by setting 'default_recipients' on the context,
then don't overwrite the content with the method '_get_default_sms_recipients'.
For example, as an employee is a mail.thread, then the method '_get_default_sms_recipients'
exists on it. Calling this method will erase the content of the field 'recipients' that comes
from the default_recipients key in the context.
If we want to use this wizard on something else than a partner, we should avoid this
kind of overwrite.
Yannick Tivisse
3c91ac425f