Remove tobiko job from the periodic queue

This job is broken in the unmaintained/xena and unmaintained/wallaby
branches and it was agred on last Neutron CI meeting to remove it from
the periodic queue in those unmaintained branches.

Change-Id: Iaa4a4b0f4b3a75b85073a89bc37754bcd95208e5

zuul.d/job-templates.yaml

@@ -100,8 +100,6 @@
         - neutron-ovn-tempest-mariadb-full
         - neutron-ovn-tempest-ovs-release
         - neutron-ovn-tempest-ovs-release-ipv6-only
-        - devstack-tobiko-neutron:
-            voting: true
         - ironic-tempest-ipa-wholedisk-bios-agent_ipmitool-tinyipa
         - openstacksdk-functional-devstack-networking
         - neutron-linuxbridge-tempest-plugin-scenario-nftables