Add a missing null object check

We now have a null object instead of null values and
there was a place where we returned null instead of
the correct null object.

bug:28423485

Change-Id: I2626768acdf8d19fc94aa5e978eb057818450fa5
diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
index db720bb..5ff9c0c 100644
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProvider.java
@@ -846,7 +846,7 @@
 
                 // Special case for location (sigh).
                 if (isLocationProvidersAllowedRestricted(name, callingUserId, owningUserId)) {
-                    return null;
+                    continue;
                 }
 
                 Setting setting = mSettingsRegistry.getSettingLocked(
@@ -871,7 +871,8 @@
 
         // Special case for location (sigh).
         if (isLocationProvidersAllowedRestricted(name, callingUserId, owningUserId)) {
-            return null;
+            return mSettingsRegistry.getSettingsLocked(SETTINGS_TYPE_SECURE,
+                    owningUserId).getNullSetting();
         }
 
         // Get the value.