Fix list of API extensions for dvr and designate jobs

For jobs running on stable branches we need to use API extensions
list correct for each branch.
This patch sets it for dvr and designate jobs where we somehow
missed it and used always extensions list from master branch.

Change-Id: I0c1dfe77711a2904850fb1a240eb7cf807722af6

.zuul.yaml

@@ -749,6 +749,7 @@
     override-checkout: stable/queens
     vars:
       branch_override: stable/queens
+      network_api_extensions_common: *api_extensions_queens
       # TODO(slaweq): remove trunks subport_connectivity test from blacklist
       # when bug https://bugs.launchpad.net/neutron/+bug/1838760 will be fixed
       tempest_black_regex: "(^neutron_tempest_plugin.scenario.test_trunk.TrunkTest.test_subport_connectivity)"
@@ -763,6 +764,7 @@
     override-checkout: stable/rocky
     vars:
       branch_override: stable/rocky
+      network_api_extensions_common: *api_extensions_rocky
       devstack_localrc:
         USE_PYTHON3: false
         TEMPEST_PLUGINS: /opt/stack/neutron-tempest-plugin
@@ -772,6 +774,7 @@
     parent: neutron-tempest-plugin-dvr-multinode-scenario
     override-checkout: stable/stein
     vars:
+      network_api_extensions_common: *api_extensions_stein
       branch_override: stable/stein
 
 - job:
@@ -809,6 +812,7 @@
     override-checkout: stable/queens
     vars:
       branch_override: stable/queens
+      network_api_extensions_common: *api_extensions_queens
       devstack_localrc:
         USE_PYTHON3: false
         TEMPEST_PLUGINS: '"/opt/stack/designate-tempest-plugin /opt/stack/neutron-tempest-plugin"'
@@ -820,6 +824,7 @@
     override-checkout: stable/rocky
     vars:
       branch_override: stable/rocky
+      network_api_extensions_common: *api_extensions_rocky
       devstack_localrc:
         USE_PYTHON3: false
         TEMPEST_PLUGINS: '"/opt/stack/designate-tempest-plugin /opt/stack/neutron-tempest-plugin"'
@@ -829,6 +834,7 @@
     parent: neutron-tempest-plugin-designate-scenario
     override-checkout: stable/stein
     vars:
+      network_api_extensions_common: *api_extensions_stein
       branch_override: stable/stein
 
 - job: