[svn-r22114] 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#.


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

tools/h5diff/testfiles/h5diff_486.txt

@@ -0,0 +1,11 @@
+
+file1     file2
+---------------------------------------
+    x      x    /              
+    x      x    /dset1         
+
+group  : </> and </>
+0 differences found
+dataset: </dset1> and </dset1>
+0 differences found
+EXIT CODE: 0