Bug#855937: apt-get's error messages don't include its name.

[Ralph Corderoy <ralph-debianbug@inputplus.co.uk>]

Package: apt
Version: 1.2.19

Running apticron, manually or by cron, results in

    E: Held packages were changed and -y was used without --allow-change-held-packages.

Using strace, I found this is from one of the commands it runs and can
trigger it directly.

    # /usr/bin/apt-get -q -y --ignore-hold --allow-unauthenticated \
    >     -s dist-upgrade
    Reading package lists...
    Building dependency tree...
    Reading state information...
    Calculating upgrade...
    The following held packages will be changed:
      hhvm
    The following packages will be upgraded:
      hhvm
    1 to upgrade, 0 to newly install, 0 to remove and 0 not to upgrade.
    E: Held packages were changed and -y was used without --allow-change-held-packages.
    #

apt-get should be producing error messages that start with its program
name, as is the Unix tradition, otherwise tracking down the culprit from
scripts and pipelines is more difficult.