COMP: build liblas with gdal only when gdal version is 1.6 or greater
COMP: build liblas with gdal only when gdal version is 1.6 or greater

orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB,orfeotoolbox/OTB