Make explicit the network backend used in the CI jobs

All Neutron CI jobs (except for unit, functional and fullstack jobs),
have explicitly defined the network backend used:
- linuxbridge
- ovs
- ovn

That was discussed and approved during the Neutron CI meetings [1].

[1]https://meetings.opendev.org/meetings/neutron_ci/2021/neutron_ci.2021-06-15-15.00.log.html

Depends-On: https://review.opendev.org/c/openstack/neutron/+/797051
Change-Id: Ib14542311e9b1d49829bef54f433b8a04709a9fd
diff --git a/.zuul.yaml b/.zuul.yaml
index 3c490ff..f8435a5 100644
--- a/.zuul.yaml
+++ b/.zuul.yaml
@@ -730,11 +730,11 @@
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
-        - neutron-grenade-multinode:
+        - neutron-ovs-grenade-multinode:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
-        - neutron-tempest-linuxbridge:
+        - neutron-linuxbridge-tempest:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
@@ -767,11 +767,11 @@
         - devstack-multinode
         - devstack-unit-tests
         - openstack-tox-bashate
-        - neutron-grenade-multinode:
+        - neutron-ovs-grenade-multinode:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
-        - neutron-tempest-linuxbridge:
+        - neutron-linuxbridge-tempest:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
@@ -824,11 +824,11 @@
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
-        - neutron-tempest-dvr:
+        - neutron-ovs-tempest-dvr:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$
-        - neutron-tempest-dvr-ha-multinode-full:
+        - neutron-ovs-tempest-dvr-ha-multinode-full:
             irrelevant-files:
               - ^.*\.rst$
               - ^doc/.*$