Fix NPE crash in UsageAccessDetails

mPackageInfo will be null in RefreshUI method in UsageAccessDetails.java

Bug:https://issuetracker.google.com/issues/65872768
Test:As explained in the link above

Change-Id: I8bd4b822cfe5d8a3347ca7f5886605cbdfb9b8b6
Signed-off-by: tiansiming <tiansiming@xiaomi.com>

src/com/android/settings/applications/AppInfoBase.java

@@ -214,7 +214,9 @@ public abstract class AppInfoBase extends SettingsPreferenceFragment
 
     @Override
     public void onPackageListChanged() {
-        refreshUi();
+        if (!refreshUi()) {
+            setIntentAndFinish(true, true);
+        }
     }
 
     public static void startAppInfoFragment(Class<?> fragment, int titleRes,