Deduplicate opbeat errors
Deduplicate opbeat errors

Previously, errors were logged twice in opbeat, and once for every url.
This is very inconvenient, as exceptions are not grouped by type of
error.
The only advantage of manually logging exceptions as errors is to
visualize the corresponding url easily, but that information is easily
retrieved from opbeat.

StartupsPoleEmploi/labonneboite,StartupsPoleEmploi/labonneboite,StartupsPoleEmploi/labonneboite,StartupsPoleEmploi/labonneboite