Check if mediafile was already saved
Check if mediafile was already saved

This fixes a bug introduced in 2d299f05fd6339fa001ec31ada48426ba234b913
where every image was marked as binary (which was a fix for
http://github.com/matthiask/feincms/issues/closed#issue/71. The problem was
that self.file no longer points to the file object once the item has
already been saved.

michaelkuty/feincms,matthiask/feincms2-content,feincms/feincms,matthiask/feincms2-content,mjl/feincms,feincms/feincms,pjdelport/feincms,joshuajonah/feincms,nickburlett/feincms,matthiask/django-content-editor,michaelkuty/feincms,matthiask/feincms2-content,hgrimelid/feincms,michaelkuty/feincms,nickburlett/feincms,pjdelport/feincms,hgrimelid/feincms,matthiask/django-content-editor,joshuajonah/feincms,joshuajonah/feincms,matthiask/django-content-editor,pjdelport/feincms,mjl/feincms,joshuajonah/feincms,matthiask/django-content-editor,feincms/feincms,mjl/feincms,nickburlett/feincms,hgrimelid/feincms,michaelkuty/feincms,nickburlett/feincms