Get rid of fullname override parameter

With the introduction of the Additional name fields in Moodle 2.6 (MDL-31776 - Additional name fields), we tried setting the setting $CFG->fullnamedisplay to take advantage of this new feature. However, there are several places in Moodle in which the fullname() function is passed with the $override parameter and our $CFG->fullnamedisplay setting is ignored.

Why is the $override flag needed? Does it still make sense with the "Additional name fields" feature?

Here is a list of places in Moodle in which the override flag is set:

admin/registration/form.php
admin/settings/server.php
admin/user (multiple files call it)
admin/user.php
course/lib.php
course/loginas.php
course/recent_forms.php
enrol/invitation/unenrolusers.php
enrol/unenrolusers.php
enrol/users.php
group/autogroup.php
group/index.php
group/overview.php
lib/classes/session/manager.php
lib/filebrowser/file_info_context_user.php
lib/moodlelib.php
lib/navigationlib.php
lib/odslib.class.php
lib/outputrenderers.php
lib/tests/moodlelib_test.php
lib/tests/session_manager_test.php
local/gradebook
login/change_password.php
mod/chat/report.php
mod/data/preset.php
mod/kalvidassign/locallib.php
mod/lesson/report.php
mod/quiz/attemplib.php
report/log/graph.php
report/stats/locallib.php
moodle/user

Discussion thread: https://moodle.org/mod/forum/discuss.php?d=265025