Removes try except block from creation of database tables

In case there is an error connecting to the database engine, or the database
is not yet created, POL should fail. This is specially relevant to avoid race
conditions in Docker and K8s deployments using MySQL/MariaDB, because peewee
needs the database to already exist.

Change-Id: Iabe46c1c4f718919e10fc65271d0e814c5f9a146
Signed-off-by: Benjamin Diaz <bdiaz@whitestack.com>