Use Fedora 40 guest image on 2024.1 devstack-tobiko-neutron jobs

F41 guest VMs sometimes fail to run the "first-boot-command" that tobiko
uses to customize them and create a vlan interface. This only affects
2024.1 jobs.

Due to that, devstack-tobiko-neutron jobs running on 2024.1 branch will
use F40 images instead.

Depends-On: https://review.opendev.org/c/x/tobiko/+/958875

Closes-ticket: TOBIKO-179
Change-Id: I24bc3e97194286d9a06116562a392e2395382258

zuul.d/devstack-tobiko-neutron.yaml

@@ -41,11 +41,28 @@
     name: devstack-tobiko-neutron
     parent: devstack-tobiko
     voting: true
-    branches: ^(unmaintained|stable)/(2024|2025\.1).*$
+    branches: ^(unmaintained|stable)/2024\.1
     description: |
       Base Tobiko devstack job to execute scenario+faults+scenario test cases.
-      Variant applied (at this moment) to stable branches 2024.1, 2024.2 and
+      Variant applied (at this moment) to branch 2024.1.
-      2025.1.
+    vars:
+      <<: *FAULTS_VARS
+      test_conf:
+        topology:
+          devstack_neutron_service: 'q-svc'
+      download_images_override:
+        advanced_vm:
+          url: "https://archives.fedoraproject.org/pub/archive/fedora/linux/releases/40/Cloud/x86_64/images/Fedora-Cloud-Base-Generic.x86_64-40-1.14.qcow2"
+    irrelevant-files: *FAULTS_IRRELEVANT_FILES
+
+- job:
+    name: devstack-tobiko-neutron
+    parent: devstack-tobiko
+    voting: true
+    branches: ^(unmaintained|stable)/(2024\.2|2025\.1).*$
+    description: |
+      Base Tobiko devstack job to execute scenario+faults+scenario test cases.
+      Variant applied (at this moment) to branches 2024.2 and 2025.1.
     vars:
       <<: *FAULTS_VARS
       test_conf: