refs #9048 Coverity warning CID 1075687

https://scan6.coverity.com:8443/reports.htm#v29240/p10083/fileInstanceId=11026259&defectInstanceId=3876757&mergedDefectId=528792
refs #9048 fixing Coverity noise for CompareMDWorkspaces.cpp

https://scan6.coverity.com:8443/reports.htm#v29240/p10083/fileInstanceId=11026543&defectInstanceId=3878116&mergedDefectId=528435
refs #9048 Coverity noise in IMDEventWorkspace

https://scan6.coverity.com:8443/reports.htm#v29240/p10083/fileInstanceId=11024017&defectInstanceId=3877305&mergedDefectId=528995
initialized m_FileNeedsUpdating, though I do not think it is necessary/used any more.