hdf5

[svn-r27133] - Add a new attribute function characterstic for format:
  * H5_ATTR_FORMAT(X,Y,Z)  __attribute__((format(X, Y, Z)))
- Rename UNUSED attribute characterstic to H5_ATTR_UNUSED.
- Rename NORETURN attribute characterstic to H5_ATTR_NORETURN

tested with h5committest.