D12728: KFileItemActions: fallback to default mimetype when selecting only files

[Elvis Angelaccio]

elvisangelaccio added a dependency: D12727: Introduce 
KFileItemListProperties::isFile().

REPOSITORY
  R241 KIO

REVISION DETAIL
  https://phabricator.kde.org/D12728

To: elvisangelaccio, #frameworks, dfaure
Cc: michaelh, ngraham, bruns