Fixes bug where using Execution the Hive sources no longer append data.

The hack we do in the Hive parquet sources no longer works so this is a work around. The benefit this has is that we can now choose which sources are append and which one's aren't.
Hmm, looks like dumb copy-paste overlook. Should I add support for append in HiverParquetScroogeSource in Ebenezer?