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>

DEVELOPERS

@@ -212,7 +212,6 @@ F:	package/mjpg-streamer/
 F:	package/mplayer/
 F:	package/perl-crypt-openssl-random/
 F:	package/perl-crypt-openssl-rsa/
-F:	package/perl-db-file/
 F:	package/perl-digest-sha1/
 F:	package/perl-encode-detect/
 F:	package/perl-encode-locale/