Updated openstack/openstack
Project: openstack/heat  54d20e633d73bf5e0438b73c5cdcfd6308008f6d

Fix dead link in cfn template doc

The link referenced in templates/cfn/WordPress_Single_Instance
is dead. Looks like the directory was restructured. Updated using
a like for the F18 version of the template.

Change-Id: I46705cd31e2be6f3f131c64944665eabe6347dc9