Comment out sendMail method in SOGoDraftObject and replace its sole known usage by sendMailAndCopyToSent.

In a 2011-09-26 commit (in Changelog.old), I understand the author wanted to
phase sendMail out and replace it by sendMailAndCopyToSent. Since there are
compilation warnings related to sendMail, removing the sendMail method and
replacing the sole call to it seemed like the cleanest way.