Move pFlyOnly into properties container

Change-Id: I64dcaba589f77cc5bd9241c6adb34dbe029ad9f1
Reviewed-on: https://gerrit.libreoffice.org/12481
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>