Fix #390: No longer depend on return value of add-row handler.
Fix #390: No longer depend on return value of add-row handler.

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