Caracal: Remove unnecessary kolla_enable_heat flag in ci-aio env

Heat is now disabled by default, so we don't need to disable it in the
ci-aio environment.

Author: markgoddard

etc/kayobe/environments/ci-aio/stackhpc-ci.yml

@@ -5,9 +5,6 @@
 # Docker namespace to use for Kolla images. Default is 'kolla'.
 kolla_docker_namespace: stackhpc-dev
 
-# Disable some services to reduce memory footprint.
-kolla_enable_heat: false
-
 ###############################################################################
 # StackHPC configuration.