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\173 cookiecutter._env_name \175\175/overrides.yml" "b/\173\173 cookiecutter._env_name \175\175/overrides.yml"
index ca9d34a..7fac712 100644
--- "a/\173\173 cookiecutter._env_name \175\175/overrides.yml"
+++ "b/\173\173 cookiecutter._env_name \175\175/overrides.yml"
@@ -19,6 +19,7 @@
       user:
         root:
           password: $6$oV7iKxfx$7DOZUfLw30d/W.pzUf97F0z1JhxgNmFAiKT1HhIodjkWb0M/.dTYAc3uxDCScR3lvCALjRe4/xWtiDyywf8wi1
+      purge_repos: true
   salt:
     minion:
       log: