Ensure logs path exists when initializing logs

Otherwise, for example, if we start datastore alone
like we do in the tests, we try to create logs without
the directory and traceback.
Workaround to enable start of activities still using service_name

While we deprecated service_name a long time ago, still there are activities
using it, and is a source of frequent problems.

Signed-off-by: Gonzalo Odiard <gonzalo@laptop.org>
Release 0.100.0