hdf5

Fixed HDFFV-10586 and HDFFV-10588
Description:
    HDFFV-10586 CVE-2018-17434  Divide by zero inh5repack_filters
        Added a check for zero value
    HDFFV-10588 CVE-2018-17437  Memory leak in H5O_dtype_decode_helper
        This is actually an Invalid read issue.  It was found that the
        attribute name length in an attribute message was corrupted,
        which caused the buffer pointer to be advanced too far and later
        caused an invalid read.
        Added a check to detect attribute name and its length mismatch.  The
        fix is not perfect, but it'll reduce the chance of this issue when a
        name length is corrupted or the attribute name is corrupted.
Platforms tested:
    Linux/64 (jelly)
    Linux/64 (platypus)
    Darwin (osx1010test)