hdf5

[svn-r21904] This is a followup commit for Issue 7756 - Creating a dataset in a read-only file caused seg fault when the file is closed.  I changed the error ID from H5E_CACHE to H5E_OHDR in the error report macro in H5O_create and fixed a minor problem in tfile.c.

Tested on jam and MacGoblin - minor changes.