Revert "Changes Story uniqueness validations based on entry_id and id instead of permalink and id"

This reverts commit fca8431c9d38224e968d1cec814178b7d9bad63a.

Conflicts:
	db/migrate/20130805113712_update_stories_unique_constraints.rb
Revert "Sets length for indexes in migrations"

This reverts commit f7b359a6426d081293cff7410e1622a8d7de863e.
Revert "Changes Story uniqueness validations based on entry_id and id instead of permalink and id"

This reverts commit 5394ed6782c6ded58c493380c32abaf31fdf77b9.
Changes Story uniqueness validations based on entry_id and id instead of permalink and id