Removed logging statements
Fixed issue updating Video.title with tasks (#1463)

Added code to fix it and also a migration to fix legacy data.  I've
already run the SQL for this migration a couple times on production so
when we deploy it shouldn't need to fix too many rows.

Also fixed issue running video_changed_tasks() when completing tasks.
I'm not sure what happened with the old code, but it looks like an
editing error caused totally crazy code to be there.
Added management command to fix blank video titles (#1463)