hdf5_ep

[svn-r19051] Purpose:
Add --no-dangling-links option to h5ls. 

Description:
Related to "Bug 1830 - Following an dangling external link in h5ls should set non-zero return code."
If --no-dangling-links option is specified and any dangling link is found, return exit code 1 (error).

Tested:
 jam, amani and heiwa