Add CINDER_SECURE_DELETE flag.

Defaults to true which means no change in behavoir.  Adds option
to disable secure delete as in https://review.openstack.org/15477.

Change-Id: I2b19ed4223460b550026ad4975080c0079c8b433
diff --git a/lib/cinder b/lib/cinder
index 81bfbfe..d24212d 100644
--- a/lib/cinder
+++ b/lib/cinder
@@ -134,6 +134,10 @@
         iniset $CINDER_CONF DEFAULT rabbit_password $RABBIT_PASSWORD
     fi
 
+    if [[ "$CINDER_SECURE_DELETE" == "False" ]]; then
+        iniset $CINDER_CONF DEFAULT secure_delete False
+    fi
+
     if [ "$LOG_COLOR" == "True" ] && [ "$SYSLOG" == "False" ]; then
         # Add color to logging output
         iniset $CINDER_CONF DEFAULT logging_context_format_string "%(asctime)s %(color)s%(levelname)s %(name)s [%(request_id)s %(user_id)s %(project_id)s%(color)s] %(instance)s%(color)s%(message)s"