No need to check for received unactive cells for the rho communication...

No need to check for received unactive cells for the rho communication sub-type. They can't happen any more.

src/runner.c

@@ -1535,10 +1535,8 @@ void *runner_main(void *data) {
           if (t->subtype == task_subtype_tend) {
             cell_unpack_ti_ends(ci, t->buff);
             free(t->buff);
-          } else if (t->subtype == task_subtype_xv) {
-            runner_do_recv_part(r, ci, 1);
-            /* Only need to update h_max if the cell has active particles */
-          } else if (t->subtype == task_subtype_rho && cell_is_active(ci, e)) {
+          } else if (t->subtype == task_subtype_xv ||
+                     t->subtype == task_subtype_rho) {
             runner_do_recv_part(r, ci, 1);
           } else if (t->subtype == task_subtype_gpart) {
             runner_do_recv_gpart(r, ci, 1);