Fixes a bug in db-load that sometimes deadlocks UDF execution
Fixes a bug in db-load that sometimes deadlocks UDF execution

e.g., ext_word_features_by_ext_features in chunking example

It seems the compounded redirection (via /dev/stdin in nested shells)
was not working nicely with the named pipes used by local compute
driver, failing to signal the end of data.

HazyResearch/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,HazyResearch/deepdive