Execute router commands with admin client (2)

The API calls that change the router external gateway info "enable_snat"
flag are, by default, allowed only for admin users. That fix is proposed
to the Neutron API definitions in [1].

This patch amends the missing bits of [2].

[1]https://review.opendev.org/c/openstack/neutron-lib/+/941631
[2]https://review.opendev.org/c/openstack/neutron-tempest-plugin/+/941689

Related-Bug: #2098109
Change-Id: Ie496dec0e2396a232c4e4a891672e70f0d90857f
diff --git a/neutron_tempest_plugin/api/test_routers.py b/neutron_tempest_plugin/api/test_routers.py
index 15bac41..1470a7b 100644
--- a/neutron_tempest_plugin/api/test_routers.py
+++ b/neutron_tempest_plugin/api/test_routers.py
@@ -377,7 +377,7 @@
         router = self._create_router(data_utils.rand_name('router'))
         self.assertEqual(len(router['external_gateways']), 0)
 
-        res = self.client.router_add_external_gateways(
+        res = self.admin_client.router_add_external_gateways(
             router['id'],
             [{'network_id': CONF.network.public_network_id,
               'enable_snat': False}])
@@ -391,7 +391,7 @@
         router = self._create_router(data_utils.rand_name('router'))
         self.assertEqual(len(router['external_gateways']), 0)
 
-        res = self.client.router_add_external_gateways(
+        res = self.admin_client.router_add_external_gateways(
             router['id'],
             [
                 {'network_id': CONF.network.public_network_id,
@@ -452,7 +452,7 @@
         router = self._create_router(data_utils.rand_name('router'))
         self.assertEqual(len(router['external_gateways']), 0)
 
-        res = self.client.router_add_external_gateways(
+        res = self.admin_client.router_add_external_gateways(
             router['id'],
             [
                 {'network_id': CONF.network.public_network_id,
@@ -483,7 +483,7 @@
         router = self._create_router(data_utils.rand_name('router'))
         self.assertEqual(len(router['external_gateways']), 0)
 
-        res = self.client.router_add_external_gateways(
+        res = self.admin_client.router_add_external_gateways(
             router['id'],
             [
                 {'network_id': CONF.network.public_network_id,
@@ -506,7 +506,7 @@
                     remove_gateways[0])
 
         external_gateways[1] = remove_gateways[0]
-        res_update_gws = self.client.router_update_external_gateways(
+        res_update_gws = self.admin_client.router_update_external_gateways(
             router['id'],
             external_gateways)