Merge branch 'rav/null_default_device_displayname' into develop

synapse/storage/schema/delta/33/devices_for_e2e_keys.sql

@@ -16,4 +16,4 @@
 -- make sure that we have a device record for each set of E2E keys, so that the
 -- user can delete them if they like.
 INSERT INTO devices
-    SELECT user_id, device_id, 'unknown device' FROM e2e_device_keys_json;
+    SELECT user_id, device_id, NULL FROM e2e_device_keys_json;

synapse/storage/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql

@@ -0,0 +1,20 @@
+/* Copyright 2016 OpenMarket Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+-- a previous version of the "devices_for_e2e_keys" delta set all the device
+-- names to "unknown device". This wasn't terribly helpful
+UPDATE devices
+    SET display_name = NULL
+    WHERE display_name = 'unknown device';