Bug#363389: apt: Explicit zero epoch in package version causes endless upgrading
Usually, an epoch value is either absent, and so zero implicitly, or
explicitly present and greater than zero.
If a package version number includes an explicit epoch value of zero,
apt-get misbehaves, considering the version present in the available
download sources to be newer than the installed version, *despite* them
being the exact same version!
This causes the affected package to be reinstalled every time an
'apt-get upgrade' or 'apt-get dist-upgrade' is performed.
Whilst there isn't any particularly reason for a package to include a
zero epoch value explicitly, apt should handle such a situation
This bug was discovered because mailman 0:2.1.7-2.1.8rc1-1 included an
explicit zero epoch.