qt: Return const pointer to JobPrivate class for const pointer to Job
* lang/qt/src/job.cpp, lang/qt/src/job_p.h (getJobPrivate): Replace with two overloads for non-const pointer and const pointer to Job. * lang/qt/src/job_p.h (jobPrivate): Replace with two template functions for non-const pointer and const pointer to Job.
This helps avoid changing values stored in the JobPrivate class in
const functions (e.g. getters) of Job classes.
- GnuPG-bug-id: T6530