quick fix for functions not being drawn

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35511 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
4.9.306.0

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@35512 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e