changed PROTECT code for crdMAT

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgeos@434 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
tidy

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgeos@435 edb9625f-4e0d-4859-8d74-9fd3b1da38cb