Safely fail when logs cannot be found
Safely fail when logs cannot be found

On first runs, this logfile is not going to be found. This
is causing ansible to crash and stop applying puppet in consecutive
nodes.

Add a condition to safely fail, and abort play if no files can
be found.

Change-Id: I22a5ebbcaa603b25920fd638211f3663e81e09b0

openstack-infra/ansible-puppet,openstack-infra/ansible-puppet