Do not add a newline ('\n') between rows while running a BINARY COPY protocol.

Do not add a newline ('\n') between rows while running a BINARY COPY protocol.

PostgreSQL's BINARY COPY protocol does not expect a newline character between
rows. But coordinator was adding this while running the protocol between
coordinator and the datanodes. While Postgres-XL had some provision to deal
with this on the datanode side, it seemed either insufficient or buggy as
evident during tests with pglogical. So get rid of that and make the protocol
same as vanilla PG.