HDVHANDLER-183, fix the 0-length array handling and the format_constraint index checking.
HDVHANDLER-183, fix the 0-length array handling and the format_constraint index checking.

OPENDAP/hdf5_handler,OPENDAP/hdf5_handler,OPENDAP/hdf5_handler,OPENDAP/hdf5_handler,OPENDAP/hdf5_handler,OPENDAP/hdf5_handler