Fix bug not handling presentations that were taken down

Taken down presentation urls get redirect to an error page.
Currently the scraper just logs the crash and skip the item.
A different approach would be to check if a redirect was done
to an error page.

Change-Id: I61ea1e1c2c2473745cc918ee8dce2019ec9e7d3f
Improve log message for not found overviews

Change-Id: I7bdb1af6b1734cc918c9c980125e5cc096a97c0e
Reformat code

Change-Id: I68c3a839e7aef03b46570574fe82b996ef19a414