Refs #11244 fix xml output file

[VickieLynch]

XML output works in LoadParameterFile now;

    LoadIsawPeaks(Filename='MANDI_801.peaks', OutputWorkspace='peaks')
    LoadIsawUB(InputWorkspace='peaks', Filename='MANDI_801.mat')
    SCDCalibratePanels(PeakWorkspace='peaks',DetCalFilename='mandi_801.DetCal',XmlFilename='mandi_801.xml',a=74,b=74.5,c=99.9,alpha=90,beta=90,gamma=60)
    Load(Filename='MANDI_801_event.nxs', OutputWorkspace='MANDI_801_event')
    CloneWorkspace(InputWorkspace='MANDI_801_event', OutputWorkspace='MANDI_801_event_xml')
    LoadParameterFile(Workspace='MANDI_801_event_xml', Filename='mandi_801.xml')
    RenameWorkspace(InputWorkspace='MANDI_801_event_xml', OutputWorkspace='MANDI_801_event_DetCal')
    LoadIsawDetCal(InputWorkspace='MANDI_801_event_DetCal', Filename='mandi_801.DetCal')

~

[FedeMPouzols]

This fixes issue #11244.

[FedeMPouzols]

All looks good, this seems to fix the issue and the modified test script posted on the trac issue worked well for me locally (tested on debian).

For the future it would be great if the example script included in the .rst file is turned into a doc-test, so we protect this functionality. For that doc-test the modified/simplified version posted on trac is probably better/faster, as it only uses the two small .peaks and .mat files.