Wait longer time for FIP to be updated by L3 agent

In test test_floating_ip_update we should wait a bit more than
15 seconds for FIP to be actually updated and moved to new server
by the L3 agent.
So lets wait 60 seconds which is default value in wait_unti_true()
function.

Change-Id: I25e85af8e626664c0a562ea0a5b8faf8b29210a5
Closes-Bug: #1897326
diff --git a/neutron_tempest_plugin/scenario/test_floatingip.py b/neutron_tempest_plugin/scenario/test_floatingip.py
index d541642..6d4d830 100644
--- a/neutron_tempest_plugin/scenario/test_floatingip.py
+++ b/neutron_tempest_plugin/scenario/test_floatingip.py
@@ -392,7 +392,6 @@
 
     same_network = None
 
-    @test.unstable_test("bug 1897326")
     @decorators.idempotent_id('1bdd849b-03dd-4b8f-994f-457cf8a36f93')
     def test_floating_ip_update(self):
         """Test updating FIP with another port.
@@ -435,8 +434,7 @@
 
         # The FIP is now associated with the port of the second server.
         try:
-            common_utils.wait_until_true(_wait_for_fip_associated,
-                                         timeout=15, sleep=3)
+            common_utils.wait_until_true(_wait_for_fip_associated, sleep=3)
         except common_utils.WaitTimeout:
             self._log_console_output(servers[-1:])
             self.fail(