Make strace and tcpdump available everywhere.

* modules/openstack_project/manifests/template.pp: Some images we
use, notably CentOS, lack strace and tcpdump which our Ubuntu images
have by default. The package names are the same across the platforms
we use, so it's safe to just ensure they're present everywhere and
be done with it.

Change-Id: I2fe9469c27ed8db8e718bb4923c45ad22491ed1c
Reviewed-on: https://review.openstack.org/34270
Reviewed-by: Monty Taylor <mordred@inaugust.com>
Approved: Clark Boylan <clark.boylan@gmail.com>
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Tested-by: Jenkins