Do not perform PKI setup with init-keystone

Now that generate-keystone-pki performs PKI for us, init-keystone's
calling out to keystone-manage's pki_setup is pointless, since it
just prints that the certs already exist and exits. Turn it off.

Change-Id: Iaf0eb7f74c862213b6812bb20104658378c56153
Merge "Do not perform PKI setup with init-keystone"