Cinder: only set volume_clear for LVM

This only applies to the LVM driver (when using
thick provisioning), and doesn't have any effect on
other backends like NFS, so only write the conf entry
for LVM.

Change-Id: I722ba2fa0010d9887ed9b7fdd9e050cd4694768e
diff --git a/lib/cinder b/lib/cinder
index fd96053..2e6e97a 100644
--- a/lib/cinder
+++ b/lib/cinder
@@ -250,9 +250,6 @@
                 default_name=$be_name
             fi
             enabled_backends+=$be_name,
-
-            iniset $CINDER_CONF $be_name volume_clear $CINDER_VOLUME_CLEAR
-
         done
         iniset $CINDER_CONF DEFAULT enabled_backends ${enabled_backends%,*}
         if [[ -n "$default_name" ]]; then
diff --git a/lib/cinder_backends/lvm b/lib/cinder_backends/lvm
index 497081c..e03ef14 100644
--- a/lib/cinder_backends/lvm
+++ b/lib/cinder_backends/lvm
@@ -52,7 +52,7 @@
     iniset $CINDER_CONF $be_name volume_group $VOLUME_GROUP_NAME-$be_name
     iniset $CINDER_CONF $be_name target_helper "$CINDER_ISCSI_HELPER"
     iniset $CINDER_CONF $be_name lvm_type "$CINDER_LVM_TYPE"
-
+    iniset $CINDER_CONF $be_name volume_clear "$CINDER_VOLUME_CLEAR"
 }
 
 # init_cinder_backend_lvm - Initialize volume group