Bug#674083: python-tz: Modernise & simplify packaging

[Thomas Kluyver]

Package: python-tz
Version: 2011h-1
Severity: minor

>From review when merging packaging changes into Ubuntu [1]. The debian/rules
file could be simplified following the recommendations for Python libraries
at [2].

Also, it looks like the current rules file doesn't run any tests, although it
installs a 'testing package', so maybe I'm missing something.

Thanks.

[1] https://code.launchpad.net/~takluyver/ubuntu/quantal/python-tz/merge-py3/+merge/105551
[2] http://wiki.debian.org/Python/LibraryStyleGuide