fixed uploader warning icon in AlertDialog

src/com/owncloud/android/ui/activity/Uploader.java

@@ -307,7 +307,7 @@ public class Uploader extends FileActivity
             });
             return builder.create();
         case DIALOG_NO_STREAM:
-            builder.setIcon(android.R.drawable.ic_dialog_alert);
+            builder.setIcon(R.drawable.ic_warning);
             builder.setTitle(R.string.uploader_wrn_no_content_title);
             builder.setMessage(R.string.uploader_wrn_no_content_text);
             builder.setCancelable(false);