bugfix decomposePar

- explicitly remove any previously decomposed 'mut' and 'nut' when
  decomposing fields since they can otherwise prevent the turbulence model
  from being upgraded properly.
  Removing all decomposed fields first might be a better idea in the
  long-term, but would probably be slower.

applications/utilities/parallelProcessing/decomposePar/decomposePar.C

@@ -540,6 +540,16 @@ int main(int argc, char *argv[])
 
         processorDb.setTime(runTime);
 
+        // remove files remnants that can cause horrible problems
+        // - mut and nut are used to mark the new turbulence models,
+        //   their existence prevents old models from being upgraded
+        {
+            fileName timeDir(processorDb.path()/processorDb.timeName());
+
+            rm(timeDir/"mut");
+            rm(timeDir/"nut");
+        }
+
         // read the mesh
         fvMesh procMesh
         (