tests: add basic tests for SMTP over SSL
SSL handling in mail.py wasn't covered by our test suite, therefore it was
sometimes broken. This patch introduces pretty minimal tests that only cover
the default path. We can extend it later.
Tested with python 2.6.9 and 2.7.11 on Debian sid.
.. Common link and substitution definitions.
.. |hg(1)| replace:: **hg**\ (1)
.. _hg(1): hg.1.html
.. |hgrc(5)| replace:: **hgrc**\ (5)
.. _hgrc(5): hgrc.5.html
.. |hgignore(5)| replace:: **hgignore**\ (5)
.. _hgignore(5): hgignore.5.html