Sync with what I submitted to SLE12-SP2 at sr#116013
- Modified python3-to-python2.diff : One of the changes included
there now comes in fix_connect_dialog_focus.diff.
- Create a python3-cupshelpers or python-cupshelpers package
depending on the value of the use_python3 variable.
- Require python3-cups or python-cups (and the associated
python3-cupshelpers/python-cupshelpers) depending on the case.
- Remove %py_requires: It's not really needed.
- Merge the spec file from SLE12-SP2 and GNOME:Factory
(bnc#983255).

- Do not handle template service (configure-printer@) with the
sytemd service_* macros (boo#982299).
- Add rpmlintrc to silence the warnings about it.

- Add fix_connect_dialog_focus.diff: Enable the focus on the text
entry part of the combobox in the Connect Dialog. This way, users
can edit its content and write the ip of the remote cups server
to connect to (gh#twaugh/system-config-printer#38).

- Add python3-to-python2.diff : Remove all python3 dependencies.
- Modified python3 dependencies in the spec file too to use python2
in SLE12.

- Update to GNOME 3.20 Fate#318572

- Move system-config-printer to the main package where also the
respective .desktop file is packaged.

udev-add-printer with invalid parameters (boo#942809).