Qnx: Wait for user's confirmation to setup a bar-descriptor file

In some cases, the user does't need to package the project
and the generated bar-descriptor is useless.

Change-Id: I3f3336190939ef6ded405e3e0793a956cd0e15cc
Reviewed-by: Tobias Nätterlund <tobias.naetterlund@kdab.com>
Reviewed-by: Nicolas Arnaud-Cormos <nicolas@kdab.com>