lowering the singular limit for the invertMatrix function.

to avoid failure due to singularity detection.

opm/autodiff/StandardWell_impl.hpp

@@ -1073,7 +1073,6 @@ namespace Opm
         // If it is under THP control, it will be set to be the target value.
         // TODO: a better standard is probably whether we have the table to calculate the THP value
         // TODO: it is something we need to check the output to decide.
-        const PhaseUsage& pu = phaseUsage();
         const WellControls* wc = well_controls_;
         // TODO: we should only maintain one current control either from the well_state or from well_controls struct.
         // Either one can be more favored depending on the final strategy for the initilzation of the well control