snappyHexMesh::meshRefinement: Correct mesh instance for overwrite

Must be done just before write to correct the instance in case it has changed
due to call to reorderPatches to remove zero-sized patches.

src/mesh/snappyHexMesh/meshRefinement/meshRefinement.C

@@ -2433,6 +2433,10 @@ void Foam::meshRefinement::topoChange
 
 bool Foam::meshRefinement::write() const
 {
+    // Set correct instance (for if overwrite)
+    mesh_.setInstance(name());
+    // setInstance(mesh_.facesInstance());
+
     bool writeOk = mesh_.write();
 
     // Make sure that any distributed surfaces (so ones which probably have