Bug#868769: hkt tries to open pubring.gpg which does not exist in gnupg >= 2.1

[Cody Brownstein]

Package: hopenpgp-tools
Version: 0.19.4-3

gnupgp versions 2.1 and higher store public (and private) keys in keybox
format in ~/.gnupg/pubring.kbx

hkt tries to open ~/.gnupg/pubring.gpg which is correct for gnupg
versions lower than 2.1

Because hkt tries to open ~/.gnupg/pubring.gpg which does not exist, hkt
fails with the following error:

amnesia at amnesia:~$ hkt export-pubkeys 0x9BB25A1A5C1D9108
hkt (hopenpgp-tools) 0.19.4
Copyright (C) 2012-2016  Clint Adams
hkt comes with ABSOLUTELY NO WARRANTY. This is free software, and you
are welcome to redistribute it under certain conditions.
hkt: /home/amnesia/.gnupg/pubring.gpg: openBinaryFile: does not exist
(No such file or directory)