PCC-11259 Fix toJSON output for empty property tree

Signed-off-by: Anthony Fishbeck <anthony.fishbeck@lexisnexis.com>
Merge pull request #5896 from afishbeck/wseclRestQueryNoParameters

PCC-11259 Fix toJSON output for empty property tree

Reviewed-By: Gordon Smith <gordon.smith@lexisnexis.com>
Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>