D6053: Use explicit flag values or explicit constructor instead of nullptr

[Christoph Feck]

cfeck accepted this revision.

REPOSITORY
  R236 KWidgetsAddons

BRANCH
  nonullptrforflagsplease

REVISION DETAIL
  https://phabricator.kde.org/D6053

To: kossebau, #frameworks, cfeck, kfunk
Cc: kfunk