speed-up notification tests on Windows

[Christian Boos]

I was always annoyed by the slowness of the notification tests, but never got around to address that.

While working on migrating the ticket notification templates, I finally found the issue. Rather, there were 2 issues, both related to the way we invoke smtplib.SMTP in trac.notification.mail.SmtpEmailSender.send:

• when setting host to 'localhost', the connect will go through the results of getaddrinfo, first attempting '::1', which will timeout after one second, and only then trying '127.0.0.1'; so we pass the appropriate host value directly to avoid this timeout
• when not setting local_hostname, a name resolution would take place and that can also take time on Windows (gethostbyaddr, see #3481)

The speed-up is quite nice, as this is what I have on trunk:

$ time make test=trac/ticket/tests/notification.py

Python: /c/Dev/Python2710x64/python

  Package        Version
  ----------------------------------------------------------------------------------
  Python       : 2.7.10 (default, May 23 2015, 09:44:00) [MSC v.1500 64 bit (AMD64)]
  Setuptools   : 19.2
  Genshi       : 0.7
  Babel        : 2.1.1
  sqlite3      : 2.6.0 (3.6.21)
  PySqlite     : 2.8.1 (3.7.5)
  MySQLdb      : 1.2.5
  Psycopg2     : 2.6.1 (dt dec pq3 ext lo64)
  SVN bindings : 1.9.3 (r1718519)
  Mercurial    : 3.2-rc+51-af1e3ef18120
  Pygments     : 2.1
  Textile      : not installed
  Pytz         : 2015.7
  Docutils     : 0.12
  Twill        : 0.9
  LXML         : not installed
  coverage     : 4.0.3
  figleaf      : not installed

Variables:
  PATH=C:/Dev/Python2710x64;C:/Dev/Python2710x64/Scripts;C:/Dev/VisualSVNServer35/bin;$PATH
  PYTHONPATH=.;C:/Dev/VisualSVNServer35/PythonPackages;$PYTHONPATH
  TRAC_TEST_DB_URI=
  server-options= -p 9000 -a '*,D:/Trac/envs/htdigest.BCT,BCT' -r -e D:/Trac/envs

External dependencies:
  Git version: git version 1.9.4.msysgit.1

python  setup.py -q test -s trac.ticket.tests.notification.suite
SKIP: validation of XHTML output in functional tests (no lxml installed)
..............................................................
----------------------------------------------------------------------
Ran 62 tests in 143.636s

OK

real    2m26.226s
user    0m0.015s
sys     0m0.000s

And this is with the fix:

$ time make test=trac/ticket/tests/notification.py

[...]

python  setup.py -q test -s trac.ticket.tests.notification.suite
SKIP: validation of XHTML output in functional tests (no lxml installed)
..............................................................
----------------------------------------------------------------------
Ran 62 tests in 1.724s

OK

real    0m4.321s
user    0m0.000s
sys     0m0.015s

Maybe I should backport it to 1.0-stable as well.