hdf5_ep

[svn-r18303] Description:
    Bring r18302 from trunk to 1.8 branch:

    Tweak allocation of attribute tables created from densely stored attributes
to allow for better cleanup on errors (like when the type of corruption from
Bz#1755 is encountered).

    Also, add some code to h5dump to display an error message when the
attribute iteration for an object fails.

Tested on:
    Mac OS X/32 10.6.2 (amazon) w/debug & production
    (h5committested on trunk)