Bug#1051973: tzdata: no warning about moving US/* to tzdata-legacy

[Steev Klimaszewski <steev@kali.org>]

Hello!

This also affects Postgresql Updates as the timezone is written to the
configuration file, so for example Debian testing recently upgraded
from postgresql-15 to postgresql-16 and if you attempt to follow the
instructions in /usr/share/doc/postgresql-common/README.Debian.gz you
end up getting an error message about the configuration being
incorrect (it's written in 2 places in the configuration file) if the
timezone was set to one of the now removed timezones.

-- steev