Fix WITNESS when INVARIANT_SUPPORT is defined.
Fix WITNESS when INVARIANT_SUPPORT is defined.

This fixes tinderbox breakage from r244105.

Pointed out by: adrian

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase