Allow missing fields for lucene/VCF index

Author: bbimber

jbrowse/src/org/labkey/jbrowse/model/JsonFile.java

@@ -1002,6 +1002,8 @@ private void prepareLuceneIndex(Logger log) throws PipelineJobException
             args.add(field);
         }
 
+        args.add("--allow-missing-fields");
+
         runner.execute(args);
     }