NetApp: Define 'preferred' to False instead of none

Define preferred to false instead of none in the NetApp driver
as setting it to none will trigger a traceback later on because
the database doesn't allow null values to be inserted.
"preferred" export location metadata must be set to true or
false.  warning logging is also added to the SQLAlchemy API
if a none value is used to update the export location metadata.

Change-Id: Ie7420c9286cc42eaa1361eeffe607b9b5b6b3fbd
Closes-Bug: 1703660

manila/db/sqlalchemy/api.py

@@ -2902,6 +2902,11 @@ def export_location_metadata_update(context, export_location_uuid, metadata,
         # that will not take effect using one session and we will rewrite,
         # in that case, single record - first one added with this call.
         session = get_session()
+
+        if meta_value is None:
+            LOG.warning("%s should be properly defined in the driver.",
+                        meta_key)
+
         item = {"value": meta_value, "updated_at": timeutils.utcnow()}
 
         meta_ref = _export_location_metadata_get_query(

manila/share/drivers/netapp/dataontap/cluster_mode/lib_base.py

@@ -742,7 +742,7 @@ class NetAppCmodeFileStorageLibrary(object):
             if home_node:
                 preferred = interface.get('home-node') == home_node
             else:
-                preferred = None
+                preferred = False
 
             addresses[address] = {
                 'is_admin_only': is_admin_only,

manila/tests/share/drivers/netapp/dataontap/cluster_mode/test_lib_base.py

@@ -1120,7 +1120,7 @@ class NetAppFileStorageLibraryTestCase(test.TestCase):
 
         expected = copy.deepcopy(fake.INTERFACE_ADDRESSES_WITH_METADATA)
         for key, value in expected.items():
-            value['preferred'] = None
+            value['preferred'] = False
 
         self.assertEqual(expected, result)
         mock_get_aggregate_node.assert_called_once_with(fake.POOL_NAME)

releasenotes/notes/bug-1703660-fix-netapp-driver-preferred-state-0ce1a62961cded35.yaml

@@ -0,0 +1,6 @@
+---
+fixes:
+  - |
+    Fixed the NetApp driver to report the correct value of the "preferred"
+    export location metadata where it cannot determine if there are any
+    "preferred" export locations.