Refactor reclass cloning

SALT_MODELS_REF_CHANGE SALT_MODELS_COMMIT are both exclusive. If
SALT_MODELS_REF_CHANGE is specified then it means we don't need to do a
checkout to special commit. SALT_MODELS_COMMIT is specified but
SALT_MODELS_REF_CHANGE is not, then we need to checkout that commit.

* This change refactor the logic across all templates.
* This change introduce for loop for SALT_MODELS_REF_CHANGE. Several
  commits can be specified using space as separator. Here is an example
  export SALT_MODELS_REF_CHANGE='refs/changes/12/8412/2 refs/changes/58/8458/1'
  All commits should not have any conflicts. In case of conflicts create
  dependant commits and use top one.
* The 'cmd:' for the step "Clone reclass models with submodules" was moved
  to shared-salt.yaml and included to other templates as a jinja2 'macro'.
* SALT_MODELS_SYSTEM_COMMIT now works as expected. If not specified then
  will be used the 'system' commit specified in the cluster model
  submodule.

Doc-Impact

Change-Id: I0d57b1eea79a7c011231dcf7f46fb3599a62c33f
Signed-off-by: Sergii Golovatiuk <sgolovatiuk@mirantis.com>
Reviewed-on: https://review.gerrithub.io/372906
Reviewed-by: Sergii Golovatiuk <holser@gmail.com>
Reviewed-by: Dennis Dmitriev <dis.xcom@gmail.com>
Tested-by: Dennis Dmitriev <dis.xcom@gmail.com>
diff --git a/tcp_tests/templates/virtual-mcp11-ovs/openstack.yaml b/tcp_tests/templates/virtual-mcp11-ovs/openstack.yaml
index 6f2d10c..66574ae 100644
--- a/tcp_tests/templates/virtual-mcp11-ovs/openstack.yaml
+++ b/tcp_tests/templates/virtual-mcp11-ovs/openstack.yaml
@@ -3,8 +3,8 @@
 {% from 'virtual-mcp11-ovs/underlay.yaml' import HOSTNAME_CTL02 with context %}
 {% from 'virtual-mcp11-ovs/underlay.yaml' import HOSTNAME_CTL03 with context %}
 {% from 'virtual-mcp11-ovs/underlay.yaml' import HOSTNAME_GTW01 with context %}
-{% from 'virtual-mcp11-ovs/salt.yaml' import IPV4_NET_EXTERNAL_PREFIX with context %}
-{% from 'virtual-mcp11-ovs/salt.yaml' import IPV4_NET_TENANT_PREFIX with context %}
+{% from 'shared-salt.yaml' import IPV4_NET_EXTERNAL_PREFIX with context %}
+{% from 'shared-salt.yaml' import IPV4_NET_TENANT_PREFIX with context %}
 
 # Install OpenStack control services