During the second build round in the reprotest job, the unit test suite is
failing.  This change disables the reprotest suite in order to avoid masking
pipeline failures caused by failures in other jobs.  Reprotest should be
re-enabled as soon as possible.

There were more python2 requirements than just the Depends line in
debian/tests/control.  Rather than update to python3, I replaced the tests with
equivalent bash-based tests and dropped the python dependencies entirely.

Closes: #967039

Pulled fixes for the following from upstream's svn:
https://bz.apache.org/SpamAssassin/show_bug.cgi?id=7810
https://bz.apache.org/SpamAssassin/show_bug.cgi?id=7817
https://bz.apache.org/SpamAssassin/show_bug.cgi?id=7834

Replace python with python3 in autopkgtest dependencies in support of the
python2 removal effort

Closes: #967039

Closes: #964060

Retroactively document these fixes, which were not publicly documented when
3.4.4-rc1 was released by upstream.

We don't use gbp to construct an orig tarball, since upstream sources aren't
tracked in this repository.

This lintian check is intended to identify postinst scripts that are using
s-s-d to start long-lived daemons, when invoke-rc.d should be used for that
purpose.  In spamassassin's case, s-s-d is only used to invoke the short-lived
sa-update and sa-compile programs with the appropriate uid/gid and environment.

Upstream is not entirely consistent with their tagging convention.  Case in
point, tags/spamassassin_release_3_4_4 exists, refers to 3.4.4~rc1.  This
change adds the ability to override the snapshot location, rather than deriving
it from the latest version in debian/changelog.  In general we want to use the
version from the changelog, so print a warning whenever the override is used.

    - CVE-2018-11805: Malicious rules files, possibly retrieved
      automatically via sa-update, can run arbitrary commands.
    - CVE-2019-12420: A message can be crafted in a way to use excessive
      resources, resulting in a denial of service.

Fix some issues reported by lintian

See merge request debian/spamassassin!3

Fixes lintian: uses-debhelper-compat-file
See https://lintian.debian.org/tags/uses-debhelper-compat-file.html for more details.

+ Use dh_installsystemd rather than deprecated dh_systemd_enable.
+ Use dh_installsystemd rather than deprecated dh_systemd_start.

Fixes lintian: package-uses-old-debhelper-compat-version
See https://lintian.debian.org/tags/package-uses-old-debhelper-compat-version.html for more details.

Fixes lintian: debian-watch-uses-insecure-uri
See https://lintian.debian.org/tags/debian-watch-uses-insecure-uri.html for more details.

Upstream's rule source is not included in snapshots.  Use this script to unify
the snapshot source and the rules source.