Use a uniform way to get the local path of the binaries (#10211)

Signed-off-by: bo.jiang <bo.jiang@daocloud.io>

roles/download/tasks/prep_kubeadm_images.yml

@@ -24,7 +24,7 @@
 
 - name: prep_kubeadm_images | Copy kubeadm binary from download dir to system path
   copy:
-    src: "{{ local_release_dir }}/kubeadm-{{ kubeadm_version }}-{{ image_arch }}"
+    src: "{{ downloads.kubeadm.dest }}"
     dest: "{{ bin_dir }}/kubeadm"
     mode: 0755
     remote_src: true