HPCC-10529 Wrong formatted debug log cause exception in logging.

Fix debug log message format.

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>
Merge pull request #5204 from AttilaVamos/HPCC-10529-fix

HPCC-10529 Wrong formatted debug log cause exception in logging.

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>