Set section/clause import to use new directive convention.

Per [68434850](https://www.pivotaltracker.com/story/show/68434850).  Now that clauses are connected via `DirectiveSection` it must check what the object type is before running `save_object`; failure to do so was causing the bug.

Import view function was also not passing along whether it's a section or clause import, which is important now, so that was updated as well.