Directory traversal

The (1) contrib/eqn2graph/eqn2graph.sh, (2) contrib/grap2graph/grap2graph.sh, and (3) contrib/pic2graph/pic2graph.sh scripts in GNU troff (aka groff) 1.21 and earlier do not properly handle certain failed attempts to create temporary directories, which might allow local users to overwrite arbitrary files via a symlink attack on a file in a temporary directory, a different vulnerability than CVE-2004-1296.