Don't let dlt_vopt exceptions bubble up in CreateAndConnectCfgDrive reversion

If dlt_vopt raises an exception in the reversion flow, it will mask
the original error in spawn which prompted the reversion.

Closes-Bug: #1674383

Change-Id: I6206e891c6a1df142f4438bef6776b01bd72e2dc

nova_powervm/tests/virt/powervm/tasks/test_storage.py

@@ -58,6 +58,13 @@ class TestStorage(test.TestCase):
 
         self.mock_mb.reset_mock()
 
+        # Revert when dlt_vopt fails
+        self.mock_mb.dlt_vopt.side_effect = Exception('fake-exc')
+        task.revert(lpar_w, 'mgmt_cna', 'result', 'flow_failures')
+        self.mock_mb.dlt_vopt.assert_called_once_with(lpar_w.uuid)
+
+        self.mock_mb.reset_mock()
+
         # With a specified FeedTask
         task = tf_stg.CreateAndConnectCfgDrive(
             self.adapter, 'host_uuid', self.instance, 'injected_files',

nova_powervm/virt/powervm/tasks/storage.py

@@ -14,6 +14,8 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+import six
+
 from pypowervm.tasks import scsi_mapper as pvm_smap
 
 from oslo_log import log as logging
@@ -394,8 +396,13 @@ class CreateAndConnectCfgDrive(pvm_task.PowerVMTask):
         if self.mb is None:
             return
 
-        # Delete the virtual optical media
-        self.mb.dlt_vopt(lpar_wrap.uuid)
+        # Delete the virtual optical media. If it fails we don't care.
+        try:
+            self.mb.dlt_vopt(lpar_wrap.uuid)
+        except Exception as e:
+            LOG.warning(_LW('Vopt removal as part of spawn reversion failed '
+                            'with: %(exc)s'), {'exc': six.text_type(e)},
+                        instance=self.instance)
 
 
 class DeleteVOpt(pvm_task.PowerVMTask):