fix trove image addition

the previous addition to trove was done in a way that it was not
possible to discover from nodepool. This fixes our ability to do
that, especially with non-default on services.

Change-Id: I8ca682354e0d4e2eb9cf05f40c6dd783de1c6355
diff --git a/tools/image_list.sh b/tools/image_list.sh
index f9a4e2f..0bb49ab 100755
--- a/tools/image_list.sh
+++ b/tools/image_list.sh
@@ -10,7 +10,7 @@
 DRIVERS="openvz ironic libvirt vsphere xenserver dummy"
 
 # Extra variables to trigger getting additional images.
-ENABLED_SERVICES=h-api
+export ENABLED_SERVICES="h-api,tr-api"
 HEAT_FETCHED_TEST_IMAGE="Fedora-i386-20-20131211.1-sda"
 PRECACHE_IMAGES=True