Make GDALCreateGenImgProjTransformer2() and GDALCreateGenImgProjTransformer3() fail when the creation of the reprojection transformer fails

git-svn-id: https://svn.osgeo.org/gdal/trunk@26185 f0d54148-0727-0410-94bb-9a71ac55c965
Merge branch 'trunk' of github.com:rouault/gdal into trunk_with_coverage