Fix crash when setting a password/pattern from private fragment

As of N+, we don't allow the addition of private fragments as this
causes problems with Configuration Change recreations.

Bug: 29565251
Change-Id: I6a4cf1011e1a4e6ba308565e010a51d2992e79e2

src/com/android/settings/ChooseLockPassword.java

@@ -689,7 +689,7 @@ public class ChooseLockPassword extends SettingsActivity {
         }
     }
 
-    private static class SaveAndFinishWorker extends SaveChosenLockWorkerBase {
+    public static class SaveAndFinishWorker extends SaveChosenLockWorkerBase {
 
         private String mChosenPassword;
         private String mCurrentPassword;