* lang/qt/src/qgpgmesignkeyjob.h: Remove unneeded includes. Include
<memory>.
(QGpgMESignKeyJob): Remove all member variables. Add pimpl pointer.
* lang/qt/src/qgpgmesignkeyjob.cpp: Include <QString>. Don't include
<memory>.
(QGpgMESignKeyJob::Private): New.
(QGpgMESignKeyJob::QGpgMESignKeyJob): Remove initialization of removed
members. Initialize d.
(QGpgMESignKeyJob::start, QGpgMESignKeyJob::setUserIDsToSign,
QGpgMESignKeyJob::setCheckLevel, QGpgMESignKeyJob::setExportable,
QGpgMESignKeyJob::setSigningKey, QGpgMESignKeyJob::setNonRevocable,
QGpgMESignKeyJob::setRemark, QGpgMESignKeyJob::setDupeOk): Adapt to move
of member variables to pimpl.