Prepare for LVM based VCP

This patch adds metadata needed to setup partitions on
VCP with LVM.

The new param 'image_layout' is added to salt:control:size:<size_name>
This is metadata that describes partition layout of VCP.

For now VCP has predefined list of partitions see
https://gerrit.mcp.mirantis.com/#/c/30862/

image_layout defines sizes for each of partitions that should be
applied after VCP is provisioned. The resizing will be done by
growlvmp.py script placed on VCP
https://gerrit.mcp.mirantis.com/#/c/31052/

The default layout:

  image_layout:
    root:
      size: '30%VG'     # 30% of VG total size
    home:
      size: '1G'        # fixed size 1G
    var_log:
      size: '11%VG'     # 11% of VG total size
    var_log_audit:
      size: '5G'        # fixed size 5G
    var_tmp:
      size: '11%VG'     # 11% of VG total size
    tmp:
      size: '5G'        # fixed size 5G

Related-Prod: PROD-24537

Change-Id: I18205dfa8478be2ae092a87ced833c8ab0cc01ea
diff --git a/salt/control/cluster/openstack_benchmark_single.yml b/salt/control/cluster/openstack_benchmark_single.yml
index 43ea18f..c8223cc 100644
--- a/salt/control/cluster/openstack_benchmark_single.yml
+++ b/salt/control/cluster/openstack_benchmark_single.yml
@@ -1,6 +1,13 @@
 parameters:
   _param:
     openstack_benchmark_backend_image: ${_param:salt_control_trusty_image_backend}
+    salt_control_cluster_node_cloud_init_openstack_benchmark:
+      user_data:
+        write_files:
+        - content: |
+            ${salt:control:size:openstack.benchmark:image_layout}
+          owner: root:root
+          path: /usr/share/growlvm/image-layout.yml
   salt:
     control:
       size:
@@ -9,6 +16,7 @@
           ram: 4096
           disk_profile: small
           net_profile: default
+          image_layout: ${_param:salt_control_cluster_node_image_layout_openstack_benchmark}
       cluster:
         internal:
           domain: ${_param:cluster_domain}
@@ -20,3 +28,4 @@
               image: ${_param:salt_control_trusty_image}
               backend: ${_param:openstack_benchmark_backend_image}
               size: openstack.benchmark
+              cloud_init: ${_param:salt_control_cluster_node_cloud_init_openstack_benchmark}