#3307 restore_slashbox_defaults overwrites timezone

[David T.]

hitting the "restore default slashboxes" in
preferences/homepage overwrites the saved timezone
with "-1200 International Date Line West". Just need to
add 'tzcode' => 1 in users.pl,

to this function call:
if ($form->{restore_slashbox_defaults}) {
setToDefaults($user_edits_table, {
...