remove kube bridge on reset (#4250)

roles/network_plugin/kube-router/tasks/reset.yml

@@ -7,3 +7,16 @@
 - name: reset | remove the network device created by kube-router
   command: ip link del kube-dummy-if
   when: kube_dummy_if.stat.exists
+
+- name: check kube-bridge exists
+  stat:
+    path: /sys/class/net/kube-bridge
+  register: kube_bridge_if
+
+- name: reset | donw the network bridge create by kube-router
+  command: ip link set kube-bridge down
+  when: kube_bridge_if.stat.exists
+
+- name: reset | remove the network bridge create by kube-router
+  command: ip link del kube-bridge
+  when: kube_bridge_if.stat.exists