Avoid re-creation of mP repository

By setting CREATE_NEW_DATABASE to "if_needed" we avoid re-running
of database initialization code in midpoint-data container on
re-creation of that container. (Although almost harmless it could
cause problems in some situations.)

midpoint/docker-compose.yml

@@ -10,8 +10,8 @@ services:
     volumes:
      - midpoint_mysql:/var/lib/mysql
      - midpoint_data:/var/lib/mysqlmounted
-#    environment:
-#     - CREATE_NEW_DATABASE=if_needed
+    environment:
+     - CREATE_NEW_DATABASE=if_needed
 
   midpoint-server:
     build: ./midpoint-server/