HPCC-11212 Fix problems with SOAPCALL to a blank url.

Signed-off-by: Gavin Halliday <gavin.halliday@lexisnexis.com>
Merge pull request #5681 from ghalliday/issue11212

HPCC-11212 Fix problems with SOAPCALL to a blank url.

Reviewed-By: Richard Chapman <rchapman@hpccsystems.com>