drop osm_water_lakeline and osm_water_point tables before creating new ones

layers/water_name/update_water_name.sql

@@ -20,6 +20,8 @@ FROM osm_water_polygon AS wp
 WHERE wp.name <> ''
   AND ST_IsValid(wp.geometry);
 
+DROP TABLE IF EXISTS osm_water_lakeline CASCADE;
+
 -- etldoc:  osm_water_polygon ->  osm_water_lakeline
 -- etldoc:  lake_centerline  ->  osm_water_lakeline
 CREATE TABLE IF NOT EXISTS osm_water_lakeline AS
@@ -75,6 +77,8 @@ SELECT osm_id,
        is_intermittent
 FROM osm_water_point_view;
 
+DROP TABLE IF EXISTS osm_water_point CASCADE;
+
 -- etldoc:  osm_water_point_earth_view ->  osm_water_point
 CREATE TABLE IF NOT EXISTS osm_water_point AS
 SELECT *