Fix for issue where image is compile with flag ENABLE_DHCP_GRAPH_SERVICE (#4573)

and then we load image and reboot even if there was existing
config_db.json we will look for DHCP Service. we should disbale
update_graph in such cases. This behaviour is silimar to what we have in
201811 image.

Author: abdosi

files/image_config/config-setup/config-setup

@@ -310,6 +310,8 @@ do_config_migration()
             # Migrate the DB to the latest schema version if needed
             /usr/bin/db_migrator.py -o migrate
         fi
+        # Disable updategraph
+        disable_updategraph
     elif [ -r ${MINGRAPH_FILE} ]; then
         echo "Use minigraph.xml from old system..."
         reload_minigraph