Exist layer creation via gdal_contour produce incorrect error message

[bishop]

Сreating contours layer using gdal_contour in PostGIS

gdal_contour -a elev -f PostgreSQL -i 50 -nln new_isolines dem.tif "PG:host=localhost port=5432 dbname=mybase user=postgres password=postgres"

produce an error message

ERROR 1: Layer new_isolines already exists, CreateLayer failed.
Use the layer creation option OVERWRITE=YES to replace it.

if the layer exist in database.

But gdal_contour don't support -lco option

[bishop]

Added dsco and lco options. Fixed in r25643