hdf5_ep

[svn-r4701] 
Purpose:
   bug fixed
Description:
   HDF4 Vdata is extensible, when converted, the new HDF4 data set should also be extensible.
Solution:
   Make the HDF4 dataset converted from Vdata unlimited dimensions.
   These three testing files should be updated accordingly.
Platforms tested:
Linux, RedHat 6.2