fix hammer setup postgresql 15

There are multiple unit tests failures on jenkins. When I looked into this there is an error:

$ sudo /usr/local/sbin/kea-admin db-init pgsql -u keatest -p keatest
Checking if there is a database initialized already...
Initializing database using script /usr/local/share/kea/scripts/pgsql/dhcpdb_create.pgsql
psql:/usr/local/share/kea/scripts/pgsql/dhcpdb_create.pgsql:36: ERROR:  permission denied for schema public
LINE 1: CREATE TABLE lease4 (
                     ^
ERROR/kea-admin: Database initialization failed, status code: 3?

looks like ALTER DATABASE keatest OWNER TO keatest; fixes this