Bugfix: order of function arguments.

Order of arguments for computePhaseFlowRatesPerWell() was wrong.
This fix was done previously for SimulatorCompressibleTwophase,
but the incompressible sim was ignored.

Also added an ASSERT that may help catch some misuse.

opm/core/utility/miscUtilities.cpp

@@ -553,6 +553,7 @@ namespace Opm
     {
         const int np = wells.number_of_phases;
         const int nw = wells.number_of_wells;
+        ASSERT(int(flow_rates_per_well_cell.size()) == wells.well_connpos[nw]);
         phase_flow_per_well.resize(nw * np);
         for (int wix = 0; wix < nw; ++wix) {
             for (int phase = 0; phase < np; ++phase) {