Modified .Rbuildignore to get rid of CRAN warning about the .forgebump file

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/oompa@222 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Modified .Rbuildignore to get rid of CRAN warning about the .forgebump file

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/oompa@223 edb9625f-4e0d-4859-8d74-9fd3b1da38cb