module-xml: WSDL namespace error regression

[davidnich]

This is an error from a valid WSDL validated with SoapUI that was working in previous versions of the WSDL module:

User exception: /Users/david/src/Qorus/test/qlib/WSDL.qm:4152 (Qore): WSDL-NAMESPACE-ERROR: imported schema uses prefix \"ns1\" to refer to \"http://jif.ntswincash.com/h3git/arreceipts\", however this prefix was previously defined with \"http://jif.ntswincash.com/h3git/arreceipts/webservice\"
call stack:
  Namespaces::merge() called at /Users/david/src/Qorus/test/qlib/WSDL.qm:4665 (Qore user code)
  WebService::parseTypes() called at /Users/david/src/Qorus/test/qlib/WSDL.qm:4919 (Qore user code)
  WebService::doInit() called at /Users/david/src/Qorus/test/qlib/WSDL.qm:4455 (Qore user code)
  WebService::constructor() called at ServiceApi.qc:881 (Qore user code)
  ServiceApi::registerSoapHandler() called at qorus-service-api.ql:588 (Qore user code)
  svc_register_soap_handler() called at service method: it-86-ar_receipts-wincash-in v1.0 (34) init (16472):30 (Qore source \"/Users/david/src/drei/sepl-it/src/86-AR_RECEIPTS/msepl_it/it-86-ar_receipts-wincash-in-v1.0.qsd\":46 user code)
  init() called at <builtin>:-1 (Qore user code)
  Program::callFunctionArgs() called at LocalQorusService.qc:635 (Qore builtin code)
  Service::callMethodImpl() called at AbstractQorusCoreService.qc:267 (Qore user code)
  AbstractQorusCoreService::callMethod() called at AbstractQorusCoreService.qc:125 (Qore user code)
  AbstractQorusCoreService::init() called at ServiceManager.qc:1735 (Qore user code)
  ServiceManager::loadInternal() called at ServiceManager.qc:1825 (Qore user code)
  ServiceManager::loadService() called at ServiceManager.qc:1568 (Qore user code)
  ServiceManager::autoStartServiceBackground() called at ServiceManager.qc:1558 (Qore user code)
  *** thread started by background operator ***", info: {type: "user", name: "it-86-ar_receipts-wincash-in", version: "1.0"}