Do not run after_boot.sh by default

Do not run after_boot.sh by default

In the definition of the stack in openstack-rapid.yaml, we define a
CloudConfig resource. after_boot.sh is called automatically by
a service (check-prox-system-setup.service), after each boot. In this
file, defined in the CloudConfig resource, you can put instructions
needed for succesful operation and to fix certain issues in your
environment. By default, this file should NOT be executed, hence we
should not have this in the CloudConfig. Change the name back to
after_boot.sh if you need to execute this code.

Change-Id: Ifd3f86fe6dfd31444b799833d6b435a310708f25
Signed-off-by: Luc Provoost <luc.provoost@intel.com>