check_i18n.py and tests are not included in dist tarball

[lcorreia]

./run_tests.sh

---

Ran 0 tests in 0.000s

OK
make[3]: Leaving directory '/home/dev/tarball/wok-2.3.0/src/wok/plugins/ginger/tests'
make[2]: Leaving directory '/home/dev/tarball/wok-2.3.0/src/wok/plugins/ginger/tests'
make[1]: Leaving directory '/home/dev/tarball/wok-2.3.0/src/wok/plugins/ginger/tests'
make[1]: Entering directory '/home/dev/tarball/wok-2.3.0/src/wok/plugins/ginger'
while read L && test -n "$L"; do
dir=mo/$L/LC_MESSAGES ;
/bin/mkdir -p $dir ;
ln -sf ../../../po/$L.gmo $dir/ginger.mo ;
done < po/LINGUAS
make check-local
make[2]: Entering directory '/home/dev/tarball/wok-2.3.0/src/wok/plugins/ginger'
contrib/check_i18n.py ./i18n.py
/bin/bash: contrib/check_i18n.py: No such file or directory