Settings: fix typo in settings namespace for qr scanner on ls

its in secure and not in global

Change-Id: I2ec4d93a25f9aed3e9db2151c72fb21918905cdc

src/com/android/settings/display/QRCodeScannerPreferenceController.java

@@ -64,7 +64,7 @@ public class QRCodeScannerPreferenceController extends TogglePreferenceControlle
     @OnLifecycleEvent(ON_START)
     public void onStart() {
         mContentResolver.registerContentObserver(
-                Settings.Global.getUriFor(SHOW_QR_CODE_SCANNER_SETTING), false,
+                Settings.Secure.getUriFor(SHOW_QR_CODE_SCANNER_SETTING), false,
                 mSettingsObserver);
     }