Add lvm backend for cinder-volume

Add purge_repos: true to overrides.yaml

Change disk name for lvm

Change-Id: I75a144829d00fa06169c4e4315b2dc9bec796799
diff --git "a/\173\043 roles \043\175/features_lvm_backend" "b/\173\043 roles \043\175/features_lvm_backend"
new file mode 100644
index 0000000..61dedbe
--- /dev/null
+++ "b/\173\043 roles \043\175/features_lvm_backend"
@@ -0,0 +1,9 @@
+{#-
+parameters:
+  reclass:
+    storage:
+      node:
+        <reclass_storage_node_name>:
+          classes:
+#}
+          - environment.{{ cookiecutter._env_name }}.features.lvm_backend