Move image update cron back
Move image update cron back

Now that we are almost completely dib image based the image update cron
first builds all of the images which needs about 4 hours then proceeds
to upload these images to the various cloud regions. Move the cron entry
back 3 hours and 40 minutes so that image builds run then uploads happen
roughly when we had previously expected these updates (~1400UTC).

This is not strictly required but should shift uploads back in the day
allowing us to make more changes to nodepool later in our working hours
without killing uploads.

Change-Id: I1f125c944c8fd23aafdce2fc0682454b4b2c264d

Tesora/tesora-project-config,dongwenjuan/project-config,Tesora/tesora-project-config,openstack-infra/project-config,openstack-infra/project-config,dongwenjuan/project-config