Remove all traces of using Gravatar without transport security
Summary:
This was effectively disabled in the UI already, but code that doesn't
exist also can't accidentally be reactivated :)
Reviewers: KDE PIM, mlaurent
Reviewed By: KDE PIM, mlaurent
Subscribers: mlaurent
Tags: KDE PIM
Differential Revision: https://phabricator.kde.org/D7408