Update logging example to use the django logger

[SimonSteinberger]

The first example config for Django's new logger still includes the old logger:

​https://docs.djangoproject.com/en/1.9/topics/logging/#configuring-logging

'loggers': {
    'django.request': {
        'handlers': ['file'],
        'level': 'DEBUG',
        'propagate': True,
    },
},

Should be:

    'loggers': {
        'django': {
            'handlers': ['file'],
            'level': 'DEBUG',
            'propagate': True,
        },
    },

[Tim Graham]

The example is still valid if you only want to capture output from the 'django.request` logger, but I agree a better example would be to use the 'django' logger.

[Tim Graham]

Left some comments on the ​pull request.

[Tim Graham <timograham@…>]

In 483e0091:

Fixed #25959 -- Updated logging example to use the django logger.

[Tim Graham <timograham@…>]

In fa217662:

[1.9.x] Fixed #25959 -- Updated logging example to use the django logger.

Backport of 483e0091e3891dc4ed898ea0dbf6923c166f0674 from master