raise_nested_attributes_record_not_found was changed to a bang method in Rails 4.0

Obviously this gem should call the bang method now too.

The change happened here and is included in the 4.0 relase: https://github.com/rails/rails/pull/10123
Merge pull request #20 from t27duck/fix_for_banged_method

raise_nested_attributes_record_not_found was changed to a bang method in 4.0