Remove py39 jobs and fix functional job

Remove py39 jobs and reference from setup.cfg.
Functional sswan job started to fail after [1]
reorganized the L3 agent initialization, some changes
are necessary in vpnaas functional framework after that.

[1]: https://review.opendev.org/c/openstack/neutron/+/949135

Change-Id: I0edc4db80a2b712ca3c2dd664bf6a598d3407bd4

.zuul.yaml

@@ -8,7 +8,7 @@
       - release-notes-jobs-python3
     check:
       jobs:
-        - openstack-tox-py39:
+        - openstack-tox-py310:
             required-projects:
               - openstack/neutron
         - openstack-tox-py312:
@@ -22,7 +22,7 @@
         - neutron-tempest-plugin-vpnaas-ovn
     gate:
       jobs:
-        - openstack-tox-py39:
+        - openstack-tox-py310:
             required-projects:
               - openstack/neutron
         - openstack-tox-py312:

neutron_vpnaas/tests/functional/strongswan/test_strongswan_driver.py

@@ -181,6 +181,7 @@ class TestStrongSwanScenario(test_scenario.TestIPSecBase):
                               'vpnagent')
         self.agent = neutron_l3_agent.L3NATAgentWithStateReport('agent1',
                                                                 self.conf)
+        self.agent.init_host()
         self.vpn_agent = vpn_agent.L3WithVPNaaS(self.conf)
         vpn_service = mock.Mock()
         vpn_service.conf = self.conf

releasenotes/notes/drop-py39-ffff9f6d0ecfdcf3.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - |
+    Python 3.9 support has been dropped. The last release of neutron-vpnaas
+    to support py39 is Openstack 2025.1 (Epoxy).
+    For details about supported runtimes in Openstack 2025.2 please check:
+    https://governance.openstack.org/tc/reference/runtimes/2025.2.html

setup.cfg

@@ -6,7 +6,7 @@ description_file =
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 home_page = https://docs.openstack.org/neutron-vpnaas/latest/
-python_requires = >=3.9
+python_requires = >=3.10
 classifier =
     Environment :: OpenStack
     Intended Audience :: Information Technology
@@ -17,7 +17,6 @@ classifier =
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3.11
     Programming Language :: Python :: 3.12