hdf5_ep

[svn-r5313] 
Purpose:
    added more tests to the H5set_extent function
Description:

 there was a bug in the H5S_select_fill call when the fill value was not defined
 added 2 more set of tests that call H5set_extent without the fill value being defined
 there are now 4 sets of tests:
 Test H5Dset_extent with chunks on the raw data cache, with and without fill value
 Test H5Dset_extent with chunks written to file (b-tree routines),  with and without fill value

Platforms tested:
    w2000
    linux