fix for error in own recent change, sculpt triangulate was done on a bmesh with uninitialized faces normals,
add warning that BM_mesh_bm_from_me() dosn't calculate face normals.


git-svn-id: https://svn.blender.org/svnroot/bf-blender/trunk/blender@54271 954f8c5b-7b00-dc11-b283-0030488c597c