ROBUSTNESS: Added more sanity checks to tests/GenericDataFile.R to help potential troubleshooting.  From the R-Forge logs, it could be that this test manage to remove all or parts of the temporary R.filesets installation causing the next test tests/GenericDataFileSet.R to fail with "Error in library("R.filesets") : there is no package called 'R.filesets'".

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r-dots@1976 edb9625f-4e0d-4859-8d74-9fd3b1da38cb