hdf5_ep

[svn-r17415] Description:
	Bring r17408, 17411, 17412, 17413 & 17414 from trunk back to 1.8 branch:

r17408:
	Move flush operation on mounted file hierarchy into H5Fmount module.

r17411:
	Make H5AC_flush just flush the cache and make H5AC_dest perform the
proper parallel synchronization before destroying the cache.  Also, further
discriminate between 'closing' and 'non-closing' actions in H5F_flush.

r17412:
	Seperate 'flush' functionality from 'destroy' functionality at the
H5F level also.

r17413:
	Remove vestigial intermediate routine for flushing file and move it
into API routine.  Also, remove private, unused (now) 'H5F_FLUSH_DOWN' symbol
from public header file.

r17414:
	Flush the core VFD's buffer before closing the file, also flush the
metadata accumulator before reseting it.  Write the driver info message out
in the superblock flush routine more directly, instead of using wrapper
routine, since the wrapper routine won't work when the superblock is being
shutdown.

Tested on:
       FreeBSD/32 6.3 (duty) in debug mode
	(h5committest performed on trunk)