Windows: Skip policy assembly for now

On XP there is a bug which prevents two installers from including a
policy assembly of the same name.  Policy Assembly names are

  <Product>.<Major>.<Minor>

For now do not install the policy assembly until we have a work around
for XP or a method of conditionally not installing the policy on XP.

Change-Id: If92bea3c625e6124eb64c2bcc3e5008a58f04404