Remove dynamic summaries for "On the lockscreen"

Bug:36101902
Test: make RunSettingsRoboTests
Change-Id: Ie004f07f4c543a99c2b2ad1e5d7c8b2ef49246d5

src/com/android/settings/notification/LockScreenNotificationPreferenceController.java

@@ -281,6 +281,7 @@ public class LockScreenNotificationPreferenceController extends PreferenceContro
             return;
         }
         mLockscreenSelectedValue = getSummaryResource();
+        mLockscreen.setSummary("%s");
         mLockscreen.setValue(Integer.toString(mLockscreenSelectedValue));
     }