BUG: nearWallDist not updated throughout optimisation loops

Partially fixes #2502 (see discussion there)

src/optimisation/adjointOptimisation/adjoint/displacementMethod/displacementMethod/displacementMethod.C

@@ -128,7 +128,10 @@ void Foam::displacementMethod::update()
     mesh_.movePoints(tnewPoints());
     scalar timeAft = mesh_.time().elapsedCpuTime();
     Info<< "Mesh movement took " << timeAft - timeBef << " seconds" << endl;
-    mesh_.moving(false);
+    if (!mesh_.steady())
+    {
+        mesh_.moving(false);
+    }
 }