Use m1.small for ping test

m1.tiny does not have a large enough disk for the fedora image, but
m1.small does.  The only downside is that it is a 2 GB ram image.
However, our compute nodes now have 5 GB of RAM so there's plenty
available, and with such a short-lived VM it's likely that the
actual difference in memory used between the two is minimal.

This will allow us to remove the m1.demo flavor creation from the
overcloud deploy since it was only ever there for test purposes.

Note that this is essentially a cherry-pick of change
I6b1e35c00e51ae9da1830a1e6d714e5f0858bcdb from tripleo-common,
which unfortunately merged after tripleo.sh had been moved to this
repo.

Change-Id: Id4bf6af82c28eb5ec4f93df1a3e8ddef26be1d66

templates/tenantvm_floatingip.yaml

@@ -19,7 +19,7 @@ parameters:
   flavor:
     type: string
     description: Flavor to use for servers
-    default: 'm1.demo'
+    default: 'm1.small'
   public_net_name:
     type: string
     default: 'nova'