playbook: Add trigger script to reboot if it is required

  The invokation of the script is done manually, in future we might have a cron task

playbook/roles/vifib-kernel/files/slapos-trigger-reboot.sh

+#!/bin/bash
+
+FILE=/opt/upgrader/REBOOT_REQUIRED
+if [ -f "$FILE"]; 
+then
+	rm $FILE
+	reboot
+fi

playbook/roles/vifib-kernel/handlers/main.yml

+---
+
+- name: Mark to reboot
+  file: 
+    path: /opt/upgrader/REBOOT_REQUIRED 
+    state: touch
+    mode: u=rw,g=r,o=r

playbook/roles/vifib-kernel/tasks/main.yml

@@ -3,6 +3,7 @@
   - name: Install kernel 4.9 on debian 9.0
     apt: name=linux-image-4.9.0-9-amd64  state=latest update_cache=no
     when: ansible_distribution == "Debian" and ansible_distribution_major_version == "9"
+    notify: [ 'Mark to reboot' ]
 
   - name: Install Debian jessie-backports repository
     apt_repository: repo='deb http://ftp.debian.org/debian jessie-backports main' state=present update_cache=yes
@@ -11,6 +12,7 @@
   - name: Install kernel 4.9 on debian 8.0
     apt: name=linux-image-4.9.0-0.bpo.9-amd64  state=latest default_release=jessie-backports update_cache=yes
     when: ansible_distribution == "Debian" and ansible_distribution_major_version == "8"        
+    notify: [ 'Mark to reboot' ]
 
   - name: Install Debian jessie repository on debian 7
     lineinfile:
@@ -27,3 +29,7 @@
   - name: Dist upgrade debian 7 to debian 8
     apt: upgrade=dist update_cache=yes
     when: ansible_distribution == "Debian" and ansible_distribution_major_version == "7"
+    notify: [ 'Mark to reboot' ]
+
+  - name: create trigger reboot script
+    copy: src=slapos-trigger-reboot.sh dest=/usr/local/bin/slapos-trigger-reboot.sh mode=700