Comment # 2 on bug 918402 from Andreas Stieger

Bisected from svn://svn.debian.org/pgp-tools/caff
signing-party 1.1.12 contains caff r741, r753 fixes the issue:

svn log -r753 svn://svn.debian.org/pgp-tools -v
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r753 | guilhem-guest | 2015-01-03 12:07:11 +0100 (Sat, 03 Jan 2015) | 7 lines
Changed paths:
   M /trunk/caff/caff
   M /trunk/debian/changelog

caff: Deprecate $CONFIG{'secret-keyring'}.

Instead, the secret keyring (secring.gpg for GnuPG < 2.1,
private-keys-v1.d for GnuPG 2.1 or latter) is to be symlinked into
~/.caff/gnupghome.  Symlinks are automatically created if
~/.caff/gnupghome doesn't contain a secret keyring or directory.
Closes: #771857
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https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=771857

This was with gnupg 2.0.27