revert Giac to working version (compile problem)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33387 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e
Relatively quick, but not fully perfect fix for a problem concerning disappearing brackets (brackets were scaled to 0, and that's why they weren't showing)

git-svn-id: http://dev.geogebra.org/svn/trunk/geogebra@33388 23ce0884-8a58-47d3-bc5c-ddf1cd5b9f9e