hdf5_ep

Tentative fix for valgrind issues related to EoC.

Adds /*out*/ parameters to H5O_close() and H5F_try_close() so
that H5D/G_close() will know when H5O_close() has triggered a
file close and thus the file struct is not reliable.

Also removes the H5F_CLOSING() macro and related which were
formerly used to check if the file was closing.