Fixed #21675 -- Added app configs for contrib apps.

from django.apps import AppConfig

from django.utils.translation import ugettext_lazy as _

class AdminConfig(AppConfig):

    name = 'django.contrib.admin'

    verbose_name = _("administration")

from django.apps import AppConfig

from django.utils.translation import ugettext_lazy as _

class AdminDocsConfig(AppConfig):

    name = 'django.contrib.admindocs'

    verbose_name = _("administrative documentation")

from django.apps import AppConfig

from django.utils.translation import ugettext_lazy as _

class AuthConfig(AppConfig):

    name = 'django.contrib.auth'

    verbose_name = _("authentication and authorization")

from django.apps import AppConfig

from django.utils.translation import ugettext_lazy as _

class CommentsConfig(AppConfig):

    name = 'django.contrib.comments'

    verbose_name = _("comments")

from django.apps import AppConfig

from django.utils.translation import ugettext_lazy as _

class ContentTypesConfig(AppConfig):

    name = 'django.contrib.contenttypes'

    verbose_name = _("content types")