Fix test_update_restricted timeouts due to timestamp resolution

Updating a stack where the only resource needs replacement but is
restricted from being replaced is *very* fast. Since the test framework
relies on seeing a change in the updated_time timestamp, which has only 1s
resolution, it can easily be missed causing the test to timeout. This adds
a 1s sleep between updates that have the same expected status to ensure
that the timestamp changes.

Change-Id: Ief845a21108e925325b1b3e8f090038ccdf73b8e
Closes-Bug: #1554375
Related-Bug: #1583630
diff --git a/functional/test_update_restricted.py b/functional/test_update_restricted.py
index 1634192..d406b53 100644
--- a/functional/test_update_restricted.py
+++ b/functional/test_update_restricted.py
@@ -10,6 +10,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import time
+
 from heat_integrationtests.functional import functional_base
 
 test_template = {
@@ -105,6 +107,9 @@
             self._check_for_restriction_reason(resource_events,
                                                reason_replace_restrict))
 
+        # Ensure the timestamp changes, since this will be very quick
+        time.sleep(1)
+
         # check replace fails - with only 'replace' restricted
         self.update_stack(stack_identifier, update_template,
                           env_replace_restrict,
@@ -139,6 +144,9 @@
             self._check_for_restriction_reason(resource_events,
                                                reason_replace_restrict))
 
+        # Ensure the timestamp changes, since this will be very quick
+        time.sleep(1)
+
         # check replace fails - with only 'replace' restricted
         self.update_stack(stack_identifier, update_template,
                           env_replace_restrict,