Don't prevent loading GTiff driver even if libtiff version mismatch detected
|Reported by:||Even Rouault||Owned by:||Even Rouault|
In GDAL 1.8.0, a test has been added to detect if libtiff 3.X is loaded at runtime but GDAL was compiled against libtiff 4.0. This test disables the driver in case of mismatch, but in some cases, this might be too extreme, because users can have taken the care to link their application in an order that avoids crashes. So we just emit a warning, and if things go bad, users will have been warned...