[pkg-gnupg-maint] Bug#848580: dirmngr: upgrading from jessie fails

[Christian Hofstaedtler]

Control: reassign -1 dpkg
Control: found -1 1.18.16
Control: retitle -1 dpkg-maintscript-helper: fails if optional version is not given

Reassigning to dpkg which apparently broke dpkg-maintscript-helper
in 1.18.16.

-- 
christian hofstaedtler <zeha at debian.org>