[raster] Make sure ST_BandNoDataValue return NULL when ST_HasNoDataValue is false

[pracine]

Also:

-Make sure ST_SetBandNodataValue accept NULL as input -Get rid of ST_SetBandHasNodataValue -Get rid of ST_BandHasNodataValue and all dependencies. It should be replaced in plpgsql by (ST_BandNodataValue(rast, band) IS NULL)

Note that, ST_BandNoDataValue in order to know if the nodata value is significant, still need the flag added when implementing ST_SetBandHasNodataValue. The difference is that now ST_SetBandNodataValue controls the flag.

[jorgearevalo]

Solved in r6621.

[pracine]

So Robe,

following this change ST_SetBandHasNodataValue & ST_BandHasNodataValue do not exist anymore. They are respectively replaced by

ST_SetBandNodataValue(rast, NULL) & NOT ST_BandNodatavalue(rast) IS NULL