Fix openvswitch-iptables_hybrid ussuri branch

Overrides had a typo

Change-Id: I0ff70713425fd9154e9cc7a3a1db6e9b8adadcab
Closes-Bug: #1885114
diff --git a/zuul.d/ussuri_jobs.yaml b/zuul.d/ussuri_jobs.yaml
index d88b165..a9e578e 100644
--- a/zuul.d/ussuri_jobs.yaml
+++ b/zuul.d/ussuri_jobs.yaml
@@ -97,9 +97,9 @@
 - job:
     name: neutron-tempest-plugin-scenario-openvswitch-iptables_hybrid-ussuri
     parent: neutron-tempest-plugin-scenario-openvswitch-iptables_hybrid
-    override-checkout: stable-ussuri
+    override-checkout: stable/ussuri
     vars:
-      branch_override: stable-ussuri
+      branch_override: stable/ussuri
       network_api_extensions: *api_extensions
       devstack_localrc:
         NETWORK_API_EXTENSIONS: "{{ network_api_extensions | join(',') }}"