NFA: Test for forms changes MEDIA_URL, but it doesn't change it back (may cause test fail)

[Ales Zoulek]

/tests/regressiontests/forms/media.py changes MEDIA_URL to '​http://media.example.com/media/', but test for admin_widgets is constructed using the old MEDIA_URL.

That may cause error in

 >>> w = AdminFileWidget()
 >>> print conditional_escape(w.render('test', 'test'))

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FAIL: Doctest: regressiontests.admin_widgets.models.__test__.WIDGETS_TESTS
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Traceback (most recent call last):
  File "/home/al3x/programy/pythonpath/django/test/_doctest.py", line 2180, in runTest
    raise self.failureException(self.format_failure(new.getvalue()))
AssertionError: Failed doctest test for regressiontests.admin_widgets.models.__test__.WIDGETS_TESTS
  File "/home/al3x/programy/django_git/tests/regressiontests/admin_widgets/models.py", line unknown line number, in WIDGETS_TESTS

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File "/home/al3x/programy/django_git/tests/regressiontests/admin_widgets/models.py", line ?, in regressiontests.admin_widgets.models.__test__.WIDGETS_TESTS
Failed example:
    print conditional_escape(w.render('test', 'test'))
Expected:
    Currently: <a target="_blank" href="test">test</a> <br />Change: <input type="file" name="test" />
Got:
    Currently: <a target="_blank" href="http://media.example.com/media/test">test</a> <br />Change: <input type="file" name="test" />


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[Brian Rosner]

(In [7273]) newforms-admin: Fixed #6802 -- regressiontests/forms/media.py perserves the MEDIA_URL once finished. Thanks, ales_zoulek.