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).
Merged from hdf5 trunk r19051
Tested:
jam, amani, heiwa
