Fix scheduler disengagement in rusty

Have rusty not error when pids are missing

scheds/rust/scx_rusty/src/bpf/main.bpf.c

@@ -402,26 +402,23 @@ int dom_xfer_task(pid_t pid, u32 new_dom_id, u64 now)
 	struct dom_ctx *from_domc, *to_domc;
 	struct task_ctx *taskc;
 	struct task_struct *p;
-
 	p = bpf_task_from_pid(pid);
-	if (!p) {
-		scx_bpf_error("Failed to lookup task %d", pid);
-		return 0;
+	if (p) {
+		taskc = try_lookup_task_ctx(p);
+		if(taskc){
+			from_domc = lookup_dom_ctx(taskc->dom_id);
+			to_domc = lookup_dom_ctx(new_dom_id);
+
+			if (from_domc && to_domc && taskc){
+				dom_dcycle_xfer_task(p, taskc, from_domc, to_domc, now);
+			}
+		} else {
+			bpf_printk("Failed to lookup task ctx %d", pid);
+		}
+		bpf_task_release(p);
+	} else {
+		bpf_printk("Failed to lookup task %d", pid);
 	}
-
-	taskc = lookup_task_ctx(p);
-	if (!taskc)
-		goto free_task;
-
-	from_domc = lookup_dom_ctx(taskc->dom_id);
-	to_domc = lookup_dom_ctx(new_dom_id);
-
-	if (!from_domc || !to_domc || !taskc)
-		goto free_task;
-
-	dom_dcycle_xfer_task(p, taskc, from_domc, to_domc, now);
-free_task:
-	bpf_task_release(p);
 	return 0;
 }