hdf5_ep

[svn-r22124] Purpose:
  Fix for HDFFV-7837 - h5diff: incorrect behavior with exclude-path option when unique object exist only in one file

Description:
  If unique objects exists only in one file and try to exclude
  the unique objects with --exclude-path option, h5diff missed 
  excluding some objects. 
  Fixed to exclude objects correctly in such case.
  Test cases were added and tagged with jira#.
  Merged from HDF5 trunk r22114.


Tested:
  jam (linux32-LE), koala (linux64-LE), ostrich (linuxppc64-BE), tejeda (mac32-LE), linew (solaris-BE),  Windows (32-LE cmake), Cmake (jam)