Fix issue with etcd arm host installation case (#4589)

Use host_architecture variable.

roles/etcd/tasks/install_host.yml

 ---
 - name: install | Copy etcd and etcdctl binary from download dir
   copy:
-    src: "{{ local_release_dir }}/etcd-{{ etcd_version }}-linux-amd64/{{ item }}"
+    src: "{{ local_release_dir }}/etcd-{{ etcd_version }}-linux-{{ host_architecture }}/{{ item }}"
     dest: "{{ bin_dir }}/{{ item }}"
     mode: 0755
     remote_src: yes