Merge pull request #525 from leonidg/leonidg-misc

Fix an edge case that caused the bug in #475 to sometimes reoccur
Merge pull request #526 from leonidg/leonidg-mirroring

Leonidg mirroring
Merge pull request #527 from leonidg/leonidg-mirroring

Use MEDIA_ARCHIVES_ROOT in service_link_assets
Wrapped tasks in try with logging.
Removed text and source capture task.
Add poke mirrors task and fix root server bug in settings.py