[REF] db: simplify list_dbs

When trying to list db's, the db_user is searched and verified before
searching for the databases.
As it's enclosed in a db.cursor context manager, we can assume that
there is a db user at this very moment.
This commit uses a single query to find databases that belongs to this
cursor user.

Also, this commit adds a message in the logs when an exception occurs
to facilitate debugging instead of silently returning an empty list.

0 files changed, 0 insertions, 0 deletions