AppVeyor: 13 errors due to TracError: Cannot load Python bindings for SQLite

[Jun Omae]

​https://ci.appveyor.com/project/edgewall-org/trac/builds/29943185

======================================================================
ERROR: test_abs_href (trac.tests.env.EnvironmentTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\projects\trac\trac\tests\env.py", line 61, in setUp
    self.env = Environment(env_path, create=True)
  File "C:\projects\trac\trac\core.py", line 124, in __call__
    self.__init__(*args, **kwargs)
  File "C:\projects\trac\trac\env.py", line 289, in __init__
    self.create(options)
  File "C:\projects\trac\trac\env.py", line 612, in create
    DatabaseManager(self).init_db()
  File "C:\projects\trac\trac\db\api.py", line 250, in init_db
    connector, args = self.get_connector()
  File "C:\projects\trac\trac\db\api.py", line 339, in get_connector
    raise TracError(connector.error)
TracError: Cannot load Python bindings for SQLite
...
Ran 1915 tests in 559.667s
FAILED (errors=13)
make: *** [Makefile:445: unit-test] Error 1