DEVELOPERS: remove perl-db-file
Package perl-db-file was removed today:
https://git.buildroot.net/buildroot/commit/?id=8546ff31c58b2501a69e49bc0f27a4ffa1d2ae08
Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>