Skip admin floating IP tests if router extension is disabled

The non-admin network API floating IP tests skip if the
router or network extensions are not enabled, but the admin
floating IP API tests don't have the same checks - so this
change adds those same checks to the admin tests.

Change-Id: Ie25f22d0c0d639c44c3595ca613a717a2874e3b3
Closes-Bug: #1618523
diff --git a/tempest/api/network/admin/test_floating_ips_admin_actions.py b/tempest/api/network/admin/test_floating_ips_admin_actions.py
index baeaa0c..2686af2 100644
--- a/tempest/api/network/admin/test_floating_ips_admin_actions.py
+++ b/tempest/api/network/admin/test_floating_ips_admin_actions.py
@@ -26,6 +26,13 @@
     credentials = ['primary', 'alt', 'admin']
 
     @classmethod
+    def skip_checks(cls):
+        super(FloatingIPAdminTestJSON, cls).skip_checks()
+        if not test.is_extension_enabled('router', 'network'):
+            msg = "router extension not enabled."
+            raise cls.skipException(msg)
+
+    @classmethod
     def setup_clients(cls):
         super(FloatingIPAdminTestJSON, cls).setup_clients()
         cls.alt_floating_ips_client = cls.alt_manager.floating_ips_client