Fix (again) jira NCF-248.

So, it turns out that just freeing
the nc4_info is not enough;
The root group must also be reclaimed.
So, it appears the best approach
is to invoke an abort on the
failed file.




git-svn-id: https://sub.unidata.ucar.edu/netcdf/trunk@3166 2e3060e4-1ed8-cf1f-9cc2-9586e844a556