HPCC-9557 DFUPLUS spray: Cannot specify no quote character

Pass quote definition string from command line if defined (quote='') even it
is empty to override default value.

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #4562 from AttilaVamos/HPCC-9557-fix

HPCC-9557 DFUPLUS spray: Cannot specify no quote character

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>