Schedules do not re-build when an adunit's size is modified

[solocommand]

For reference, see JIRA CS-1944.

When line items/ads have been inserted with multiple sized creatives (600x100 and 300x250), and an ad unit targeted by those line items has it's sizes modified between the two, the schedules are not rebuilt. This means that the existing 300x250 ads are still scheduled to the adunit, even though they are now invalid.

A quick fix for this would be to re-save all line items targeting the ad unit (directly or indirectly), but a better one might be to abstract the schedule generation logic and run it in both places (line item save and adunit save).

[CaitlynKnudsvig]

Thanks Josh!!