D15103: Replace deprecated use of QWeakPointer in favor of QPointer

[Damien Caliste]

dcaliste added reviewers: leinir, danders.

REPOSITORY
  R8 Calligra

REVISION DETAIL
  https://phabricator.kde.org/D15103

To: dcaliste, #calligra:_3.0, leinir, danders
Cc: Calligra-Devel-list, cochise, vandenoever