Fix sketchy usage of new PreferenceScreen

Things get weird if you don't use PreferenceManager#createPreferenceScreen

Bug: 37216851
Test: Compiles and runs
Change-Id: I7cebec133c4f27f7eeda83c95d8acb4823f67dc4

res/xml/empty_settings.xml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!--
+  Copyright (C) 2017 The Android Open Source Project
+
+  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.
+  -->
+
+<PreferenceScreen />

src/com/android/settings/ApnSettings.java

@@ -184,8 +184,7 @@ public class ApnSettings extends RestrictedSettingsFragment implements
         mUnavailable = isUiRestricted();
         setHasOptionsMenu(!mUnavailable);
         if (mUnavailable) {
-            setPreferenceScreen(new PreferenceScreen(getPrefContext(), null));
+            addPreferencesFromResource(R.xml.empty_settings);
-            getPreferenceScreen().removeAll();
             return;
         }
 

src/com/android/settings/development/DevelopmentSettings.java

@@ -396,7 +396,7 @@ public class DevelopmentSettings extends RestrictedSettingsFragment
             // Block access to developer options if the user is not the owner, if user policy
             // restricts it, or if the device has not been provisioned
             mUnavailable = true;
-            setPreferenceScreen(new PreferenceScreen(getPrefContext(), null));
+            addPreferencesFromResource(R.xml.empty_settings);
             return;
         }