fixing warnings

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@10545 b7f1a160-662a-0410-a6d8-bea165342f16
image: MeshToImage: fixing rasterization of one mesh in one color without filling the inside

git-svn-id: svn://scm.gforge.inria.fr/svnroot/sofa/trunk@10546 b7f1a160-662a-0410-a6d8-bea165342f16