dockerdeb: add Ubuntu Trusty
One problem reported by lintian is "bad-distribution-in-changes-file unstable"
in changelog, but the current changelog for the official package in Ubuntu also
uses that distribution name (unstable), because they import from Debian. This
certainly doesn't stop the build process.
To run the tests, do:
cd tests/
python run-tests.py
See https://mercurial-scm.org/wiki/WritingTests for
more information on writing tests.