Add a way to collect test artifacts from the testbed

This bug was fixed in the package autopkgtest - 2.5

---------------
autopkgtest (2.5) unstable; urgency=low

  Behaviour changes:
  * Drop --output-dir option. It has never really been useful as it only works
    for paths in the testbed, has a confusing semantics, is redundant with
    --tmp-dir, and currently even crashes adt-run. (Closes: #729790)
  * Rename --tmp-dir option to --output-dir, as its main purpose is really to
    collect test artifacts. Keep --tmp-dir alias for backwards compatibility.
  * Drop --override-control option. It complicates the code too much for its
    very limited utility, and it was not even documented in the manpage.
  * Drop --paths-testbed (and thus also --paths-host) options. There is no
    use case for them.
  * Add short options for common command line options: -B for
    --no-built-binaries, -o for --output-dir, -l for --log-file,
    -u for --user.
  * Clean up uninteresting files from --output-dir directory.
  * Tests which want to create additional artifacts can now put them into the
    $ADT_ARTIFACTS directory. When using the --output-dir option, they will be
    copied into <outputdir>/artifacts/. Document this new feature in
    README.package-tests. (LP: #1137763)

  Packaging changes:
  * Drop obsolete autodebtest Conflicts/Replaces.
  * Update copyright years.
  * Bump Standards-Version to 3.9.5. No changes necessary.
  * CREDITS: Add myself.
  * Makefile: Support $DESTDIR, like automake.
  * Adjust sharedir* defaults in settings.make to what we actually want, and
    drop their overrides in debian/rules
  * Move debian/rules to using dh.
  * Add ./run-from-checkout script to run adt-run from the git checkout or
    source package. Change tests/adt-run to use it.
  * Add tests/run-parallel to run tests for different runners in parallel.

  Bug fixes:
  * Fix OSError crash if --output-dir/--tmp-dir does not exist.
    (Closes: #729791)
  * Pass line number to Test constructor argument, to be able to report proper
    errors instead of crashing. (side issue in #698551)
  * Fix exit code for "Unsupported" error.
  * When encountering an unsupported test, report only this test as skipped,
    not all the others in the same "Tests:" stanza.
  * README.package-tests: Test names must not contain '/'. (Closes: #698551)
  * Create manpage for adt-virt-schroot. (first half of #695974)
  * Fix "su: must be run from a terminal" failure when running as user and
    testbed doesn't provide root-on-testbed. (Closes: #648148)
  * Add bandaid to avoid mixing order of stdout and stderr in the log file
    when reporting results.

  Code cleanup:
  * Simplify logging by dropping the explicit functions for writing to stderr
    plus log, and instead set up pipes so that the whole stdout/stderr will be
    tee'd into the logfile.
  * Replace the usage of the AutoFile classes (which are underdocumented,
    magic, and hard to understand) with a more explicit and much simpler
    TestbedPath class.
  * Stop installing the redundant /etc/apt/apt.conf.d/90autopkgtest into
    testbeds, and simplify invocation of apt-get.

  New test cases:
  * Access /dev/std{out,err} in a non-root test, like the "mafft" autopkgtes...