devstack: use admin role

The last devstack patch introduced usage of the service project and a
Kuryr user, however, it was with the services role, while Kuryr needs
the 'admin' role.

Closes-bug: #1625482
Change-Id: If517f77c7aec3fad81af101ccc174167f16ae37b
Signed-off-by: Antoni Segura Puimedon <antonisp@celebdor.com>

devstack/plugin.sh

@@ -50,7 +50,7 @@ function create_kuryr_cache_dir {
 
 function create_kuryr_account {
     if is_service_enabled kuryr-libnetwork; then
-        create_service_user "kuryr"
+        create_service_user "kuryr" "admin"
         get_or_create_service "kuryr-libnetwork" "kuryr-libnetwork" \
         "Kuryr-Libnetwork Service"
     fi