tempest: Obey identity_feature_enabled.api_v2_admin in a few tests

Skip tests when the endpoint is not available, which is the case in gate
after [1]. We'll enable them back once we adopt them to v3.

[1] Ic233f6b43dd1e3cfdadff0f18aba4ea78825a996

Related-Bug: #1687544
Change-Id: I8fffc50fd45e43f34ca591416924bcf29626b21f
diff --git a/neutron/tests/tempest/api/admin/test_floating_ips_admin_actions.py b/neutron/tests/tempest/api/admin/test_floating_ips_admin_actions.py
index 72cacfa..764da2c 100644
--- a/neutron/tests/tempest/api/admin/test_floating_ips_admin_actions.py
+++ b/neutron/tests/tempest/api/admin/test_floating_ips_admin_actions.py
@@ -45,6 +45,9 @@
     @test.attr(type='negative')
     @decorators.idempotent_id('11116ee9-4e99-5b15-b8e1-aa7df92ca589')
     def test_associate_floating_ip_with_port_from_another_tenant(self):
+        if not CONF.identity_feature_enabled.api_v2_admin:
+            # TODO(ihrachys) adopt to v3
+            raise self.skipException('Identity v2 admin not available')
         body = self.admin_client.create_floatingip(
             floating_network_id=self.ext_net_id)
         floating_ip = body['floatingip']
diff --git a/neutron/tests/tempest/api/admin/test_quotas.py b/neutron/tests/tempest/api/admin/test_quotas.py
index 99ef2c3..ee53aa8 100644
--- a/neutron/tests/tempest/api/admin/test_quotas.py
+++ b/neutron/tests/tempest/api/admin/test_quotas.py
@@ -19,6 +19,9 @@
 from tempest import test
 
 from neutron.tests.tempest.api import base
+from neutron.tests.tempest import config
+
+CONF = config.CONF
 
 
 class QuotasTestBase(base.BaseAdminNetworkTest):
@@ -26,6 +29,9 @@
     @classmethod
     @test.requires_ext(extension="quotas", service="network")
     def resource_setup(cls):
+        if not CONF.identity_feature_enabled.api_v2_admin:
+            # TODO(ihrachys) adopt to v3
+            raise cls.skipException('Identity v2 admin not available')
         super(QuotasTestBase, cls).resource_setup()
 
     def _create_tenant(self):