D16165: Don't crash on invalid exiv2 data

[Igor Poboiko]

poboiko edited the summary of this revision.

REPOSITORY
  R286 KFileMetaData

REVISION DETAIL
  https://phabricator.kde.org/D16165

To: poboiko, #baloo, #frameworks
Cc: bruns, astippich, kde-frameworks-devel, ashaposhnikov, michaelh, spoorun, 
ngraham, abrahams