Remove agent veth_mtu configuration option

The ``[agent] veth_mtu`` has been deprecated since Wallaby
and is not used anywhere.

TrivialFix

Change-Id: I170cb2348910179b1b264bad2effc6f5015a27fa

neutron/conf/plugins/ml2/drivers/ovs_conf.py

@@ -197,12 +197,6 @@ agent_opts = [
                        "(gre, vxlan and/or geneve).")),
     cfg.PortOpt('vxlan_udp_port', default=n_const.VXLAN_UDP_PORT,
                 help=_("The UDP port to use for VXLAN tunnels.")),
-    cfg.IntOpt('veth_mtu', default=9000,
-               deprecated_for_removal=True,
-               deprecated_since="Yoga",
-               deprecated_reason="This parameter has had no effect since "
-                                 "the Wallaby release.",
-               help=_("MTU size of veth interfaces")),
     cfg.BoolOpt('l2_population', default=False,
                 help=_("Use ML2 l2population mechanism driver to learn "
                        "remote MAC and IPs and improve tunnel scalability.")),

releasenotes/notes/remove-agent-veth_mtu-9276f88cf8b43b8e.yaml

@@ -0,0 +1,6 @@
+---
+upgrade:
+  - |
+    The ``[agent] veth_mtu`` parameter of ML2 OVS mechanism driver
+    configuration has been removed. This parameter has had no effect since
+    the Wallaby release.