module-xml: confusing error message with WSDLLib::getWebServiceFromUrl() in the WSDL module

[davidnich]

the error message does not provide the correct file name:

unhandled QORE System exception thrown in TID 1 at 2022-02-18 11:38:57.733743 Fri +01:00 (CET) in ReadOnlyFile::readTextFile() (/export/home2/dnichols/src/Qorus/current/bin/qdp:424 (Qore builtin code))
FILE-OPEN2-ERROR: cannot open '': No such file or directory, arg: 2
call stack:
 15: RETHROW at /export/home2/dnichols/src/Qorus/current/bin/qdp:424)
 14: ReadOnlyFile::readTextFile() (/export/home2/dnichols/src/Qorus/current/qlib/FileLocationHandler/FileLocationHandlerFile.qc:90 (Qore builtin code))
 13: FileLocationHandlerFile::getTextFileImpl() (/export/home2/dnichols/src/Qorus/current/qlib/FileLocationHandler/FileLocationHandler.qc:52 (Qore user code))
 12: AbstractFileLocationHandler::getTextFile() (/export/home2/dnichols/src/Qorus/current/qlib/FileLocationHandler/FileLocationHandler.qc:267 (Qore user code))
 11: FileLocationHandler::getTextFileFromLocation() (/export/home2/dnichols/src/Qorus/current/qlib/FileLocationHandler/FileLocationHandler.qc:289-291 (Qore user code))
 10: FileLocationHandler::getFileFromLocation() (/export/home2/dnichols/src/Qorus/current/qlib/WSDL.qm:354 (Qore user code))
  9: WSDLLib::getFileFromURL() (/export/home2/dnichols/src/Qorus/current/qlib/WSDL.qm:416 (Qore user code))
  8: WSDLLib::getWSDL() (/export/home2/dnichols/src/Qorus/current/qlib/WSDL.qm:426 (Qore user code))
  7: WSDLLib::getWebServiceFromUrl() (/export/home2/dnichols/src/Qorus/current/qlib/SoapDataProvider/SoapDataProvider.qc:101 (Qore user code))
  6: SoapDataProvider::constructor() (<builtin>:-1 (Qore user code))
  5: ConstructorMethodVariant::call() (/export/home2/dnichols/src/Qorus/current/qlib/DataProvider/AbstractDataProviderFactory.qc:50 (Qore builtin code))
  4: AbstractDataProviderFactory::create() (/export/home2/dnichols/src/Qorus/current/qlib/DataProvider/DataProvider.qc:202 (Qore user code))
  3: DataProvider::getFactoryObjectFromStringUseEnv() (/export/home2/dnichols/src/Qorus/current/bin/qdp:419 (Qore user code))
  2: QdpCmd::getDataProvider() (/export/home2/dnichols/src/Qorus/current/bin/qdp:119 (Qore user code))
  1: QdpCmd::constructor() (<builtin>:-1 (Qore user code))