D26372: In qt5.15 QHash::insertMulti is deprecated now we need to use QMultiHash

[Laurent Montel]

mlaurent added a reviewer: dfaure.

REPOSITORY
  R286 KFileMetaData

REVISION DETAIL
  https://phabricator.kde.org/D26372

To: mlaurent, dfaure
Cc: kde-frameworks-devel, #baloo, hurikhan77, lots0logs, LeGast00n, 
fbampaloukas, GB_2, domson, ashaposhnikov, michaelh, astippich, spoorun, 
ngraham, bruns, abrahams