HPCC-10990 SprayFixed record should default to ""

Currently it is defaulting to 1.

Fixes HPCC-10990

Signed-off-by: Gordon Smith <gordon.smith@lexisnexis.com>
Merge pull request #5664 from GordonSmith/HPCC-10990

HPCC-10990 SprayFixed record should default to ""

Reviewed-By: Miguel Vazquez <miguel.vazquez@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>