Mount sd partitions as noatime and fix df

skolo/raspberry-pi/finalize_image.yml

 ---
 - hosts: 127.0.0.1
   connection: local
   remote_user: chrome-bot
   become_user: root
   become: yes
   become_method: sudo
   vars:
     image: /opt/rpi_img/2016-03-18-raspbian-jessie-lite.img
     # 8192 * 512
     offset_boot: 4194304
     # 131072 * 512
     offset_root: 67108864
   tasks:
     # Set up mounts in image's fstab
     - lineinfile: dest=/opt/raspberrypi/root/etc/fstab regexp=".*mmcblk0p2.*" state=absent
-    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p3  /b     ext4    defaults          0       2" state=present
-    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p5  /var   ext4    defaults          0       2" state=present
-    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p6  /tmp   ext4    defaults          0       2" state=present
-    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p7  /home/chrome-bot   ext4    defaults          0       2" state=present
+    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p3  /b     ext4    defaults,noatime          0       2" state=present
+    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p5  /var   ext4    defaults,noatime          0       2" state=present
+    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p6  /tmp   ext4    defaults,noatime          0       2" state=present
+    - lineinfile: dest=/opt/raspberrypi/root/etc/fstab line="/dev/mmcblk0p7  /home/chrome-bot   ext4    defaults,noatime          0       2" state=present
 
     # Swarming needs a /b file (which will have an SD card partition mounted to it.)
     - file: path=/opt/raspberrypi/root/b state=directory mode=0777
     # Make the hostname be set from the cmdline, not etc/hostname
     - file: path=/opt/raspberrypi/root/etc/hostname state=absent
     # Autologin to our user
     - lineinfile: dest=/opt/raspberrypi/root/lib/systemd/system/getty@.service regexp="^ExecStart.*" state=absent
     - lineinfile: dest=/opt/raspberrypi/root/lib/systemd/system/getty@.service line="ExecStart=-/sbin/agetty --autologin chrome-bot --noclear %I $TERM" state=present insertafter="\[Service\]"
 
     - name: Fixing udev rules for Android and NVIDIA devices
@@ skipping 14 matching lines @@
     - command: umount /opt/raspberrypi/root/dev
       ignore_errors: true
     - command: umount /opt/raspberrypi/root/proc
       ignore_errors: true
     - command: umount /opt/raspberrypi/root/sys
       ignore_errors: true
 
     - mount: name="/opt/raspberrypi/root" src="dontcare" fstype="auto" state="unmounted"
   handlers: