GdalOpen crash on c# if the dataset doesn't support SetNoDataValue (with PAM not enabled)

[aghariani]

With GDAL_PAM_ENABLED=NO

On c++: GDALOpen("egm96_15.gtx", GA_ReadOnly); Will display a warning (Error 6: SetNoDataValue() not supported for this dataset) but will not crash.

On c#: Gdal.OpenShared("egm96_15.gtx", Access.GA_ReadOnly); Will crash right away.

As it is now, I am unable to open gtx files on c#. This is linked to ticket #4660 which added a poBand->SetNoDataValue( -88.8888 );

This modification on the gtx driver is the cause of the crash.

[Even Rouault]

In 39790:

GTX: do not emit error when opening with GDAL_PAM_ENABLED=NO (fixes #6996)

[Even Rouault]

In 39791:

GTX: do not emit error when opening with GDAL_PAM_ENABLED=NO (fixes #6996)