Fix issue with is.nil for v0.1.5

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/lrgpr@143 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Try after upgrade

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/lrgpr@144 edb9625f-4e0d-4859-8d74-9fd3b1da38cb