Moodle.org sites are served via https. It would be logical to update all links to moodle.org sites to https equivalent.
So, have to performe everywhere in moodle code some search/replace, like :
Perhaps just don't modify file mod/lti/tests/locallib_test.php where on line 177 you find:
Update script should update the docroot value in mdl_config table, when it's still the default one (http://docs.moodle.org).
Changes should also be done in language packs (but perhaps in another tracker item).
Dev documentation should also reflect this change.
You can also look at the related discussion.