regenerate breaks/stalls Nitrokey Storage communication

[daringer]

to reproduce:

• insert a Nitrokey Storage
• run gpg --card-status, this works
• run ./hotp_verification regenerate 12345678 (the operation reports Operation success)
• run gpg --card-status fails:

❯ gpg --card-status
gpg: OpenPGP card not available: General error

❯ gpg --card-status
gpg: selecting card failed: No such device
gpg: OpenPGP card not available: No such device

It looks like the regenerate command somehow leads to the smartcard failing afterwards, although a power-cycle restores it again. Furthermore on my local machine restarting pcscd also fixes the issue.

This seems not to be related to a recent change inside hotp_verification but moreover it is likely related to a recent gpg version. Ultimately, I would assume hotp_verification somehow leaves the interface in a "weird" state - so the best fix is likely done in this repo here, although a workaround shall be possible in the meantime.