Revert "Protects from blank date terms."
Revert "Protects from blank date terms."

This reverts commit a3807a1fdf3016babf3f88e390a918246046b95a.

pivotal-energy-solutions/django-appsearch,pivotal-energy-solutions/django-appsearch,pivotal-energy-solutions/django-appsearch,pivotal-energy-solutions/django-appsearch