HPCC-11935 Fix Narrowing Conversions

Signed-off-by: jamienoss <james.noss@lexisnexis.com>
Merge pull request #6284 from jamienoss/issue11935-V2-fix-narrowing-conversions-when-using--std=gnu++0x

HPCC-11935 Fix Narrowing Conversions

Reviewed-by: Gavin Halliday <ghalliday@hpccsystems.com>