take care that names match in clusters and data in tabasco

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/vegan@2864 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
fix carelessness of previus commit

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/vegan@2865 edb9625f-4e0d-4859-8d74-9fd3b1da38cb