mail-handler.pl needs to not enforce PGP requirements as early in the process as it does.

[morrowc]

In working through BSG's issues it seems that:

https://github.com/ops-trust/portal/blob/master/library/mail-handler.pl#L264

should probably not test for:
'! hostmaster' && members_only && not-from-self && (undefined-member || ( !member-pgp but tg-gpg-required))

paul's suggesting that checking for GPG here is too early, and that it would be safer to check:
'! hostmaster' && members_only && not-from-self && undefined-member

and fail out as 'not valid sender' in that case instead...