hdf5_chunking_query_bmr

[svn-r12572] Description:
    Refactor new heap's header creation code to be all in the H5HFhdr.c
module.

Tested on:
   FreeBSD 4.11 (sleipnir)
   Linux/64 2.4 (mir)
   Solaris/64 2.9 (shanti)