Bug 5322

From bug 5240: there are a number of settings that can be used to
run perl code, e.g. "loadplugin", "tryplugin", "auto_whitelist_factory".
Currently these are matched in sa-update's --allowplugins code
using a regexp.  Instead, we should define a new config flag that
indicates that the current setting should be filtered out by sa-update
unless --allowplugins is set:

  push (@cmds, {
                setting => 'auto_whitelist_factory',
                is_admin => 1,
                is_update_unsafe => 1,
                default => 'Mail::SpamAssassin::DBBasedAddrList',
                type => $Mail::SpamAssassin::Conf::CONF_TYPE_STRING
               });

'is_update_unsafe' might not be the best name ;)

opened as a separate issue since I don't think it needs to be fixed for 3.2.x or
3.1.x, and I didn't want to muddy discussion of bug 5240.