set proper usage flags on list key (Closes: #148)
I think this change should do what you want, but i haven't tested it yet.
The details are derived from two places:
gpgme_op_genkey
documentation:
https://www.gnupg.org/documentation/manuals/gpgme/Generating-Keys.html
and the GnuPG manual's section on "Unattended key generation":
I haven't tested this myself! but it should address #148 (closed)