backend: Make sure the dods directory is created before starting OBS

If this doesn't exist, then the scheduler will never notify dodup that
the doddata has changed, which means that new DoD projects will never
be processed.

https://phabricator.apertis.org/T10380



Signed-off-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>


(cherry picked from commit c7eed003)

Co-authored-by: Ryan Gonzalez <ryan.gonzalez@collabora.com>