h4h5tools

Fix a bug that may occur when an SDS has unlimited dimension.

h4toh5 calls SDgetchunkinfo() to get chunking information, but this function may fail if the SDS has unlimited dimension. Since an SDS with unlimited dimension cannot be chunked, this changelist makes h4toh5 check if an SDS has unlimited dimension by calling SDisrecord(). If it has, SDgetchunkinfo() is not called; otherwise, the flow is same.

It seems SDgetchunkinfo() does not always fail even though an SDS has unlimited dimension. However, it failed for one bizarre file 2A53_CSI.971128.13.DARW.1.HDF.