Fixed test whether either ALUGrid or UG is there

Use the correct macro for UG, which is HAVE_UG.
Use logical instead of bitwise or when checking whether either ALUGrid
or UG is there.


git-svn-id: svn://svn.iws.uni-stuttgart.de/DUMUX/dumux/branches/strip-pdelab@12933 2fb0f335-1f38-0410-981e-8018bf24f1b0