Enable the volume bootable feature flag that was added in kilo

Change-Id: I5f8e0154a8b654b4c65b95f8b5c03e1a9be9e137
diff --git a/lib/tempest b/lib/tempest
index c4ae05f..0c451d3 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -451,6 +451,9 @@
     iniset $TEMPEST_CONFIG object-storage-feature-enabled discoverable_apis $object_storage_api_extensions
 
     # Volume
+    # TODO(dkranz): Remove the bootable flag when Juno is end of life.
+    iniset $TEMPEST_CONFIG volume-feature-enabled bootable True
+
     local volume_api_extensions=${VOLUME_API_EXTENSIONS:-"all"}
     if [[ ! -z "$DISABLE_VOLUME_API_EXTENSIONS" ]]; then
         # Enabled extensions are either the ones explicitly specified or those available on the API endpoint