gpgsm signatures fail starting with 2.1.0-beta864

[Jens Lechtenboerger]

Hi there,

I cannot sign messages with gpgsm any more.  beta834 was (and is)
still working, with beta864 and beta895 invalid signatures are
created:
--8<---------------cut here---------------start------------->8---
echo "Hi" > test.txt
gnupg-2.1.0-beta864/sm/gpgsm -o test.txt.sig --sign test.txt
gpgsm --verify test.txt.sig
--8<---------------cut here---------------end--------------->8---
gpgsm: invalid signature: Falsche Unterschrift

Note that I’ve got multiple keys, the first one is expired, one is
revoked, and one is valid.  Thus, I need to use --local-user to
create signatures (otherwise, the expired key is tried).

Also, I don’t know whether this makes a difference: My current key
is stored on a USB token, while the other ones are not.

Finally, if I sign with the expired key (with --faked-system-time),
then a valid signature is created.

With --debug-level guru, I don’t see noteworthy differences in the
failing and succeeding cases.

Thanks
Jens