Fix mhsign for gpg2: Expiry date format

[mmh] / etc / scan.unseen

%4(msg)%<(cur)+%| %>%<(unseen)U%| %>%<{replied}-%| %>\
%02(mon{date})/%02(mday{date})%<{date} %|*%>\
%<(mymbox{from})%<{to}To:%14(decode(friendly{to}))%>%>\
%<(zero)%17(decode(friendly{from}))%>  \
%(decode{subject})