Fix ServiceConnectionLeak in network fragment

Change-Id: I43efe9ae31fc2f58361abdb034b0205a3f3e2b71
Fix: 35957226
Test: make RunSettingsRoboTests

src/com/android/settings/core/lifecycle/ObservablePreferenceFragment.java

@@ -88,4 +88,11 @@ public abstract class ObservablePreferenceFragment extends PreferenceFragment {
         super.onPause();
     }
 
+    @CallSuper
+    @Override
+    public void onDestroy() {
+        mLifecycle.onDestroy();
+        super.onDestroy();
+    }
+
 }