Reload docker.socket after installing flannel on coreos

Workaround for #569

roles/docker/handlers/main.yml

@@ -4,6 +4,7 @@
   notify:
     - Docker | reload systemd
     - Docker | reload docker
+    - Docker | reload docker.socket
     - Docker | pause while Docker restarts
     - Docker | wait for docker
 
@@ -16,6 +17,12 @@
     name: docker
     state: restarted
 
+- name: Docker | reload docker.socket
+  service:
+    name: docker.socket
+    state: restarted
+  when: ansible_os_family == 'CoreOS'
+
 - name: Docker | pause while Docker restarts
   pause: seconds=10 prompt="Waiting for docker restart"