Storage accessors; persist nickname, flags.

Move to using new public accessors on DiskInfo and VolumeInfo.

Persist nickname changes, and remember when user has initialized a
public volume.  Also skip the migration part of storage wizard until
it's implemented.

Bug: 19993667
Change-Id: I642fb43afb95380fddd48a1dad438e87b06454da

src/com/android/settings/deviceinfo/StorageWizardMigrateConfirm.java

@@ -46,7 +46,7 @@ public class StorageWizardMigrateConfirm extends StorageWizardBase {
     @Override
     public void onNavigateNext() {
         final Intent intent = new Intent(this, StorageWizardMigrateProgress.class);
-        intent.putExtra(DiskInfo.EXTRA_DISK_ID, mDisk.id);
+        intent.putExtra(DiskInfo.EXTRA_DISK_ID, mDisk.getId());
         startActivity(intent);
         finishAffinity();
     }