Add configuration option 'image_conversion_dir' for cinder.

Cinder configuration option 'image_conversion_dir' set path to directory
used for temporary storage during image conversion.

Change-Id: Icc01549730e6b9457a88cd933b877e9968384775
Related-Prod: PROD-29437 (PROD:29437)
(cherry picked from commit edaf7481d5616bd905911c502a070b6b45a69fa1)
diff --git a/cinder/volume/single.yml b/cinder/volume/single.yml
index 9531aa4..34f5744 100644
--- a/cinder/volume/single.yml
+++ b/cinder/volume/single.yml
@@ -13,6 +13,7 @@
   cinder:
     volume:
       enabled: True
+      image_conversion_dir: ${_param:cinder_image_conversion_dir_path}
       database:
         host: ${_param:openstack_database_address}
         x509: