Fix a test that was causing problems when PyFITS is installed as root, and then the tests are run with lower privileges.
Fix a test that was causing problems when PyFITS is installed as root, and then the tests are run with lower privileges.

git-svn-id: 5305e2c1a78737cf7dd5f8f44e9bbbd00348fde7@1715 ed100bfc-0583-0410-97f2-c26b58777a21

embray/PyFITS,spacetelescope/PyFITS,spacetelescope/PyFITS,embray/PyFITS,embray/PyFITS,embray/PyFITS