disable fancy new thumbnail preview

It was causing OOMEs on old devices.
// FREEBIE

src/org/thoughtcrime/securesms/ConversationItem.java

@@ -458,11 +458,7 @@ public class ConversationItem extends LinearLayout {
         if (!messageRecord.isOutgoing()) intent.putExtra(MediaPreviewActivity.RECIPIENT_EXTRA, messageRecord.getIndividualRecipient().getRecipientId());
         intent.putExtra(MediaPreviewActivity.DATE_EXTRA, messageRecord.getDateReceived());
 
-        if (VERSION.SDK_INT >= VERSION_CODES.JELLY_BEAN) {
-          context.startActivity(intent, mediaThumbnail.getThumbnailTransition().toBundle());
-        } else {
-          context.startActivity(intent);
-        }
+        context.startActivity(intent);
       } else {
         AlertDialog.Builder builder = new AlertDialog.Builder(context);
         builder.setTitle(R.string.ConversationItem_view_secure_media_question);

src/org/thoughtcrime/securesms/MediaPreviewActivity.java

@@ -193,13 +193,6 @@ public class MediaPreviewActivity extends PassphraseRequiredActionBarActivity im
   }
 
   private void displayImage() {
-    try {
-      image.setImageBitmap(BitmapFactory.decodeStream(PartAuthority.getThumbnail(this, masterSecret, mediaUri)));
-      image.setVisibility(View.VISIBLE);
-    } catch (IOException fnfe) {
-      Log.w(TAG, "tried to render thumbnail, but it wasn't found. carrying on.");
-    }
-
     new AsyncTask<Void,Void,Bitmap>() {
       @Override
       protected Bitmap doInBackground(Void... params) {