Remove unused EnablePacemaker param from templates

Remove unused EnablePacemaker param from templates

Use of Pacemaker is governed by the resource registry since
change Ibefb80d0d8f98404133e4c31cf078d729b64dac3.

The param stayed longer in the template to prevent breakage of scripts
which could have passed it when launching stack-create, despite it being
ignored.

This change removes the param entirely.

Change-Id: I026ce391319a4306c4b81a15652e3cad470e5cb7
Depends-On: I775724b207c737043a2a418a3ec8ede2cbaa8fa0