hdf5_ep

[svn-r6901] Purpose:
Small feature.

Description:
Change the wording for the use of HDF5_PARAPREFIX from Remark to hint.
Also made process 0 be the only one printing the hint rather all
processes duplicating the same hints.

Platforms tested:
Copper, both serial and parallel.
Did not do h5commit test since this is very localized and the above
tests covered both cases already.

Misc. update: