Replace deprecated tenant_id property

The tenant_id property of RestClient in tempest was deprecated in
25.0.0. This replaces the deprecated property by the new project_id
property to avoid the following warning.

WARNING tempest.lib.common.rest_client [-] Deprecated: "tenant_id"
property is deprecated for removal, use "project_id" instead

Depends-on: https://review.opendev.org/c/openstack/tempest/+/707938
Change-Id: Ie3c32f9f2278b78603a4214c5717df8691ba490a
diff --git a/neutron_tempest_plugin/scenario/test_mtu.py b/neutron_tempest_plugin/scenario/test_mtu.py
index 31319ec..ea62fcf 100644
--- a/neutron_tempest_plugin/scenario/test_mtu.py
+++ b/neutron_tempest_plugin/scenario/test_mtu.py
@@ -101,7 +101,7 @@
 
     def _create_setup(self):
         self.admin_client = self.os_admin.network_client
-        net_kwargs = {'tenant_id': self.client.tenant_id}
+        net_kwargs = {'tenant_id': self.client.project_id}
         for net_type in ['vxlan', 'gre']:
             net_kwargs['name'] = '-'.join([net_type, 'net'])
             net_kwargs['provider:network_type'] = net_type
@@ -186,7 +186,7 @@
     def _create_setup(self):
         self.admin_client = self.os_admin.network_client
         for test_net in self._get_network_params():
-            test_net['tenant_id'] = self.client.tenant_id
+            test_net['tenant_id'] = self.client.project_id
             test_net['name'] = data_utils.rand_name('net')
             cidr = None if 'cidr' not in test_net else test_net.pop('cidr')
             network = self.admin_client.create_network(**test_net)[