[1.6.x] Fixed typo in Custom management commands documentation.

  Make sure you know what you are doing if you decide to change the value of

  this option in your custom command if it creates database content that

  is locale-sensitive and such content shouldn't contain any translations (like

  it happens e.g. with django.contrim.auth permissions) as making the locale

  it happens e.g. with django.contrib.auth permissions) as making the locale

  differ from the de facto default 'en-us' might cause unintended effects. See

  the `Management commands and locales`_ section above for further details.