Add retry to rename func

This change adds a retry to the overall rename operation.  The CI
testing has found a few etag issues from the REST API when this is
invoked and this change will provide some additional retries to ensure
that the overall rename goes through.

Change-Id: Ib68bfb72fd0b755fe065c36153c4dceffc117ebc
Closes-Bug: 1570927

nova_powervm/tests/virt/powervm/test_vm.py

@@ -444,16 +444,20 @@ class TestVM(test.TestCase):
         self.assertEqual('NewEntry', new_entry)
         self.san_lpar_name.assert_called_with(name)
 
+    @mock.patch('pypowervm.utils.transaction.entry_transaction')
     @mock.patch('nova_powervm.virt.powervm.vm.get_instance_wrapper')
-    def test_rename(self, mock_get_inst):
+    def test_rename(self, mock_get_inst, mock_entry_transaction):
         instance = objects.Instance(**powervm.TEST_INSTANCE)
 
+        mock_entry_transaction.side_effect = lambda x: x
+
         entry = mock.Mock()
         entry.update.return_value = 'NewEntry'
         new_entry = vm.rename(self.apt, 'mock_host_uuid', instance, 'new_name',
                               entry=entry)
         self.assertEqual('new_name', entry.name)
         entry.update.assert_called_once_with()
+        mock_entry_transaction.assert_called_once_with(mock.ANY)
         self.assertEqual('NewEntry', new_entry)
         self.san_lpar_name.assert_called_with('new_name')
         self.san_lpar_name.reset_mock()

nova_powervm/virt/powervm/vm.py

@@ -31,6 +31,7 @@ from pypowervm.tasks import power
 from pypowervm.tasks import vterm
 from pypowervm import util as pvm_util
 from pypowervm.utils import lpar_builder as lpar_bldr
+from pypowervm.utils import transaction as pvm_trans
 from pypowervm.utils import uuid as pvm_uuid
 from pypowervm.utils import validation as vldn
 from pypowervm.wrappers import base_partition as pvm_bp
@@ -600,12 +601,17 @@ def rename(adapter, host_uuid, instance, name, entry=None):
         be fetched.
     :returns: The updated LPAR wrapper.
     """
-
     if not entry:
         entry = get_instance_wrapper(adapter, instance, host_uuid)
 
-    entry.name = pvm_util.sanitize_partition_name_for_api(name)
-    return entry.update()
+    hyp_name = pvm_util.sanitize_partition_name_for_api(name)
+
+    @pvm_trans.entry_transaction
+    def _rename(entry):
+        entry.name = hyp_name
+        return entry.update()
+
+    return _rename(entry)
 
 
 def dlt_lpar(adapter, lpar_uuid):