[pve-devel] [RFC installer] install: do not create deprecated /etc/timezone

[Stoiko Ivanov]

starting with  tzdata version 2024b-5 [0] the package does not create
/etc/timezone anymore (background is quite well explained in
/usr/share/doc/tzdata/NEWS.Debian.gz:
```
Previously, the tzdata package in Debian used the /etc/timezone file to
configure the system's timezone. This method is not supported by systemd
and certain desktop environments, which instead only change the
/etc/localtime symlink to point to a file in /usr/share/zoneinfo.
....
In a future release, the /etc/timezone file will be automatically
removed ... The debian-installer from Trixie also no longer
creates this file.
```
align our installer with debian's installer.

[0] https://metadata.ftp-master.debian.org/changelogs//main/t/tzdata/tzdata_2025b-4_changelog
Signed-off-by: Stoiko Ivanov <s.ivanov at proxmox.com>
---
I would NOT recommend adding this patch now - we'd need to check where our
code relies on /etc/timezone being present (PVE/INotify.pm creates it IIRC,
proxmox-time create and proxmox-backup have a fallback to /etc/localtime) -
but that was just a very cursory glance at a grep '/etc/timezone' in my
source-dir).

 Proxmox/Install.pm | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Proxmox/Install.pm b/Proxmox/Install.pm
index 9cb88bc..fb23f7f 100644
--- a/Proxmox/Install.pm
+++ b/Proxmox/Install.pm
@@ -1299,7 +1299,6 @@ _EOD
         my $timezone = Proxmox::Install::Config::get_timezone();
         unlink("$targetdir/etc/localtime");
         symlink("/usr/share/zoneinfo/$timezone", "$targetdir/etc/localtime");
-        file_write_all("$targetdir/etc/timezone", "$timezone\n");
 
         unlink "$targetdir/etc/mailname";
         $postfix_main_cf =~ s/__FQDN__/${hostname}.${domain}/;
-- 
2.39.5