[pkg-gnupg-maint] Bug#835349: gnupg needs proper Breaks/Conflicts for switch to gnupg2

[Adrian Bunk]

Package: gnupg
Version: 2.1.14-5
Severity: serious

For at least #782904 and possibly other packages proper
Breaks/Conflicts are required for all packages where old versions
(especially the versions in stable) were broken to ensure that these
packages get upgraded to fixed versions when the gnupg package is
updated to the version based on gnupg2.

Otherwise users might be left with a broken combination of packages
in various partial upgrade, backport and Debian-derived distribution
scenarios.