[client] Do not load some Django's middleware modules to avoid an error.

I has got the following Django's error when I accessed '/viewer'
with a web browser, since 2 day ago.

My environment is Xubuntu 13.10 (64bit). I guess a recent update
of pacakages caused the problem. To solve it, this patch removes
the unnecessary middleware modules of the Django, which are
concerned with the issue.

-------------------------------------------
Environment:

Request Method: GET
Request URL: http://localhost:8000/viewer/ajax_users

Django Version: 1.5.4
Python Version: 2.7.5
Installed Applications:
('django.contrib.staticfiles', 'hatohol')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.middleware.locale.LocaleMiddleware')

Traceback:
File "/usr/local/lib/python2.7/dist-packages/django/core/handlers/base.py" in get_response
  92.                     response = middleware_method(request)
File "/usr/local/lib/python2.7/dist-packages/django/middleware/locale.py" in process_request
  23.             request, check_path=check_path)
File "/usr/local/lib/python2.7/dist-packages/django/utils/translation/__init__.py" in get_language_from_request
  126.     return _trans.get_language_from_request(request, check_path)
File "/usr/local/lib/python2.7/dist-packages/django/utils/translation/trans_real.py" in get_language_from_request
  390.         lang_code = request.session.get('django_language', None)
File "/usr/local/lib/python2.7/dist-packages/django/contrib/sessions/backends/base.py" in get
  55.         return self._session.get(key, default)
File "/usr/local/lib/python2.7/dist-packages/django/contrib/sessions/backends/base.py" in _get_session
  167.                 self._session_cache = self.load()
File "/usr/local/lib/python2.7/dist-packages/django/contrib/sessions/backends/db.py" in load
  18.                 expire_date__gt=timezone.now()
File "/usr/local/lib/python2.7/dist-packages/django/db/models/manager.py" in get
  143.         return self.get_query_set().get(*args, **kwargs)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py" in get
  398.         num = len(clone)
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py" in __len__
  106.                 self._result_cache = list(self.iterator())
File "/usr/local/lib/python2.7/dist-packages/django/db/models/query.py" in iterator
  317.         for row in compiler.results_iter():
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py" in results_iter
  775.         for rows in self.execute_sql(MULTI):
File "/usr/local/lib/python2.7/dist-packages/django/db/models/sql/compiler.py" in execute_sql
  840.         cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/util.py" in execute
  41.             return self.cursor.execute(sql, params)
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/base.py" in execute
  130.             six.reraise(utils.DatabaseError, utils.DatabaseError(*tuple(e.args)), sys.exc_info()[2])
File "/usr/local/lib/python2.7/dist-packages/django/db/backends/mysql/base.py" in execute
  120.             return self.cursor.execute(query, args)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/cursors.py" in execute
  201.             self.errorhandler(self, exc, value)
File "/usr/local/lib/python2.7/dist-packages/MySQLdb/connections.py" in defaulterrorhandler
  36.     raise errorclass, errorvalue

Exception Type: DatabaseError at /viewer/ajax_users
Exception Value: (1146, "Table 'hatohol_client.django_session' doesn't exist")