Enable deactivate image tests in tempest

Deactivate image is new feature, so it cannot be default
enabled in tempest.

Change-Id: Ic33b3e2f7a9f62543680647312603bdd19b90198
Depends-On: I7880f0e2646ce8660e035ebaa19a60f5bf271b64
diff --git a/lib/tempest b/lib/tempest
index 059709d..5312a02 100644
--- a/lib/tempest
+++ b/lib/tempest
@@ -329,6 +329,7 @@
     if [[ ! -z "$TEMPEST_HTTP_IMAGE" ]]; then
         iniset $TEMPEST_CONFIG image http_image $TEMPEST_HTTP_IMAGE
     fi
+    iniset $TEMPEST_CONFIG image-feature-enabled deactivate_image true
 
     # Auth
     TEMPEST_ALLOW_TENANT_ISOLATION=${TEMPEST_ALLOW_TENANT_ISOLATION:-$TEMPEST_HAS_ADMIN}